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Kishor Kumar DG, Pashupathi M, Vaidhya A, Ravi Prakash G, Bramhane A, Panigrahi M, Karikalan M, Lingaraju MC, Manickam K, Singh TU, Parida S. Involvement of ObRb receptor, nitric oxide, and BK Ca channel signaling pathways in leptin-induced relaxation of pregnant mouse uterus. Eur J Pharmacol 2024; 978:176796. [PMID: 38945286 DOI: 10.1016/j.ejphar.2024.176796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 06/27/2024] [Accepted: 06/27/2024] [Indexed: 07/02/2024]
Abstract
The purpose of this study was to determine the receptor subtype and the underlying mechanisms involved in the relaxant effect to leptin in mid- and late-pregnant mouse uterus. We determined the relative mRNA expression of receptor subtypes, eNOS, and BKCa channel by quantitative PCR and also the overall receptor expression by immunohistochemistry. Isometric tension studies were conducted to evaluate the effects of leptin and to delineate its mechanisms. A selective siRNA for the ObRb receptor was used to determine the participation of the receptor subtype in biochemical and molecular effects of leptin. The relaxant response to leptin was greater in mid-pregnancy compared to late pregnancy and was mediated by the activation of BKCa channels by eNOS-derived nitric oxide in an ObRb receptor-dependent manner. In comparison to mid-pregnancy, expression of short forms (mainly ObRa receptor) of the receptor was significantly increased in late pregnancy, whereas ObRb receptor expression was similar in both phases. The results of the study suggest that ObRb receptor mediates leptin-induced increase in eNOS expression and NO synthesis. Leptin-induced eNOS expression and activation cause cGMP-independent stimulation of BKCa channels causing uterine relaxation. Increased short forms of the receptors and reduced BKCa channels exert a negative effect on uterine relaxation in late pregnancy. Leptin may have a physiological role in maintaining uterine quiescence in mid-pregnancy and its reduced relaxant response in late gestation may facilitate labor. Further, ObRb receptor agonists may be useful in the management of preterm labor.
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Affiliation(s)
- D G Kishor Kumar
- Division of Pharmacology and Toxicology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, India, 243122
| | - M Pashupathi
- Division of Animal Biochemistry, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, India, 243122
| | - Ayushi Vaidhya
- Division of Pharmacology and Toxicology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, India, 243122
| | - G Ravi Prakash
- Division of Pharmacology and Toxicology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, India, 243122
| | - Anjali Bramhane
- Division of Physiology and Climatology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, India, 243122
| | - Manjit Panigrahi
- Division of Animal Genetics and Breeding, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, India, 243122
| | - M Karikalan
- Division of Pathology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, India, 243122
| | - Madhu C Lingaraju
- Division of Pharmacology and Toxicology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, India, 243122
| | - Kesavan Manickam
- Division of Pharmacology and Toxicology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, India, 243122
| | - Thakur Uttam Singh
- Division of Pharmacology and Toxicology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, India, 243122
| | - Subhashree Parida
- Division of Pharmacology and Toxicology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, India, 243122.
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Walewska E, Makowczenko KG, Witek K, Laniecka E, Molcan T, Alvarez-Sanchez A, Kelsey G, Perez-Garcia V, Galvão AM. Fetal growth restriction and placental defects in obese mice are associated with impaired decidualisation: the role of increased leptin signalling modulators SOCS3 and PTPN2. Cell Mol Life Sci 2024; 81:329. [PMID: 39090270 PMCID: PMC11335253 DOI: 10.1007/s00018-024-05336-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 04/05/2024] [Accepted: 06/28/2024] [Indexed: 08/04/2024]
Abstract
Decidualisation of the endometrium is a key event in early pregnancy, which enables embryo implantation. Importantly, the molecular processes impairing decidualisation in obese mothers are yet to be characterised. We hypothesise that impaired decidualisation in obese mice is mediated by the upregulation of leptin modulators, the suppressor of cytokine signalling 3 (SOCS3) and the protein tyrosine phosphatase non-receptor type 2 (PTPN2), together with the disruption of progesterone (P4)-signal transducer and activator of transcription (STAT3) signalling. After feeding mice with chow diet (CD) or high-fat diet (HFD) for 16 weeks, we confirmed the downregulation of P4 and oestradiol (E2) steroid receptors in decidua from embryonic day (E) 6.5 and decreased proliferation of stromal cells from HFD. In vitro decidualised mouse endometrial stromal cells (MESCs) and E6.5 deciduas from the HFD showed decreased expression of decidualisation markers, followed by the upregulation of SOCS3 and PTPN2 and decreased phosphorylation of STAT3. In vivo and in vitro leptin treatment of mice and MESCs mimicked the results observed in the obese model. The downregulation of Socs3 and Ptpn2 after siRNA transfection of MESCs from HFD mice restored the expression level of decidualisation markers. Finally, DIO mice placentas from E18.5 showed decreased labyrinth development and vascularisation and fetal growth restricted embryos. The present study revealed major defects in decidualisation in obese mice, characterised by altered uterine response to E2 and P4 steroid signalling. Importantly, altered hormonal response was associated with increased expression of leptin signalling modulators SOCS3 and PTPN2. Elevated levels of SOCS3 and PTPN2 were shown to molecularly affect decidualisation in obese mice, potentially disrupting the STAT3-PR regulatory molecular hub.
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Affiliation(s)
- Edyta Walewska
- Department of Reproductive Immunology and Pathology, Institute of Animal Reproduction and Food Research of Polish Academy of Sciences, Olsztyn, Poland
| | - Karol G Makowczenko
- Department of Reproductive Immunology and Pathology, Institute of Animal Reproduction and Food Research of Polish Academy of Sciences, Olsztyn, Poland
| | - Krzysztof Witek
- Laboratory of Cell and Tissue Analysis and Imaging, Institute of Animal Reproduction and Food Research of Polish Academy of Sciences, Olsztyn, Poland
| | - Elżbieta Laniecka
- Department of Reproductive Immunology and Pathology, Institute of Animal Reproduction and Food Research of Polish Academy of Sciences, Olsztyn, Poland
| | - Tomasz Molcan
- Department of Reproductive Immunology and Pathology, Institute of Animal Reproduction and Food Research of Polish Academy of Sciences, Olsztyn, Poland
| | - Andrea Alvarez-Sanchez
- Molecular Mechanisms of Placental Invasion, Centro de Investigación Príncipe Felipe, Eduardo Primo Yúfera 3, 46012, Valencia, Spain
| | - Gavin Kelsey
- Epigenetics Programme, The Babraham Institute, Cambridge, CB22 3AT, UK.
- Centre for Trophoblast Research, University of Cambridge, Cambridge, CB2 3EG, UK.
| | - Vicente Perez-Garcia
- Molecular Mechanisms of Placental Invasion, Centro de Investigación Príncipe Felipe, Eduardo Primo Yúfera 3, 46012, Valencia, Spain.
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid (UAM), 28049, Madrid, Spain.
| | - António M Galvão
- Department of Reproductive Immunology and Pathology, Institute of Animal Reproduction and Food Research of Polish Academy of Sciences, Olsztyn, Poland.
- Epigenetics Programme, The Babraham Institute, Cambridge, CB22 3AT, UK.
- Centre for Trophoblast Research, University of Cambridge, Cambridge, CB2 3EG, UK.
- Department of Comparative Biomedical Sciences, Royal Veterinary College, 4 Royal College Street, London, NW1 0TU, UK.
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Alves-Silva T, Húngaro TG, Freitas-Lima LC, de Melo Arthur G, Arruda AC, Santos RB, Oyama LM, Mori MA, Bader M, Araujo RC. Kinin B1 receptor controls maternal adiponectin levels and influences offspring weight gain. iScience 2023; 26:108409. [PMID: 38058311 PMCID: PMC10696114 DOI: 10.1016/j.isci.2023.108409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 06/16/2023] [Accepted: 11/03/2023] [Indexed: 12/08/2023] Open
Abstract
Given the importance of the kinin B1 receptor in insulin and leptin hormonal regulation, which in turn is crucial in maternal adaptations to ensure nutrient supply to the fetus, we investigated the role of this receptor in maternal metabolism and fetoplacental development. Wild-type and kinin B1 receptor-deficient (B1KO) female mice were mated with male mice of the opposite genotype. Consequently, the entire litter was heterozygous for kinin B1 receptor, ensuring that there would be no influence of offspring genotype on the maternal phenotype. Maternal kinin B1 receptor blockade reduces adiponectin secretion by adipose tissue ex vivo, consistent with lower adiponectin levels in pregnant B1KO mice. Furthermore, fasting insulinemia also increased, which was associated with placental insulin resistance, reduced placental glycogen accumulation, and heavier offspring. Therefore, we propose the combination of chronic hyperinsulinemia and reduced adiponectin secretion in B1KO female mice create a maternal obesogenic environment that results in heavier pups.
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Affiliation(s)
- Thaís Alves-Silva
- Laboratory of Genetics and Exercise Metabolism, Molecular Biology Program, Biophysics Department, Federal University of São Paulo (UNIFESP), São Paulo 04039-032, Brazil
- Max-Delbrück Center for Molecular Medicine (MDC), Campus Berlin-Buch, 13125 Berlin, Germany
| | - Talita G.R. Húngaro
- Laboratory of Genetics and Exercise Metabolism, Nephrology Program, Biophysics Department, Federal University of São Paulo (UNIFESP), São Paulo 04039-032, Brazil
| | - Leandro C. Freitas-Lima
- Laboratory of Genetics and Exercise Metabolism, Molecular Biology Program, Biophysics Department, Federal University of São Paulo (UNIFESP), São Paulo 04039-032, Brazil
| | - Gabriel de Melo Arthur
- Laboratory of Genetics and Exercise Metabolism, Molecular Biology Program, Biophysics Department, Federal University of São Paulo (UNIFESP), São Paulo 04039-032, Brazil
| | - Adriano C. Arruda
- Laboratory of Genetics and Exercise Metabolism, Nephrology Program, Biophysics Department, Federal University of São Paulo (UNIFESP), São Paulo 04039-032, Brazil
| | - Raisa B. Santos
- Laboratory of Genetics and Exercise Metabolism, Nephrology Program, Biophysics Department, Federal University of São Paulo (UNIFESP), São Paulo 04039-032, Brazil
| | - Lila M. Oyama
- Laboratory of Nutrition and Endocrine Physiology, Physiology Department, Federal University of São Paulo (UNIFESP), São Paulo 04023-901, Brazil
| | - Marcelo A.S. Mori
- Laboratory of Aging Biology, Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas (UNICAMP), São Paulo 13083-862, Brazil
| | - Michael Bader
- Max-Delbrück Center for Molecular Medicine (MDC), Campus Berlin-Buch, 13125 Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
- Institute for Biology, University of Lübeck, Lübeck, Germany
- Charité University Medicine Berlin, Berlin, Germany
| | - Ronaldo C. Araujo
- Laboratory of Genetics and Exercise Metabolism, Molecular Biology Program, Biophysics Department, Federal University of São Paulo (UNIFESP), São Paulo 04039-032, Brazil
- Laboratory of Genetics and Exercise Metabolism, Nephrology Program, Biophysics Department, Federal University of São Paulo (UNIFESP), São Paulo 04039-032, Brazil
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Butterstein GM, Hirst C, Castracane VD. Maternal serum leptin in the pregnant rat: fetal-placental implantation number and progesterone. Endocrine 2022; 76:457-464. [PMID: 35182364 DOI: 10.1007/s12020-022-02984-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 01/07/2022] [Indexed: 11/29/2022]
Abstract
PURPOSE This study was designed to determine whether there is a role of the placenta in the regulation of maternal serum leptin levels in the pregnant rat. METHODS We have adjusted the number of fetal-placental implants on day 9 in the pregnant rat by aspirating fetal-placental units to adjust the number to 1-2, 4-5 per rat or >10 in controls. Serum levels of leptin and progesterone were determined by radioimmunoassay. A separate group of pregnant rats were ovariectomized and maintained with progesterone silastic capsules (10, 20 or 40 mm). RESULTS In the pregnant rats with varied fetal-placental implant numbers, the maternal serum leptin were greatest in the group with the smallest number (1-2) of implants; intermediate in the midgroup (4-5 implants); and lowest in the group with a full complement of implantations (>10) (p < 0.001). Serum progesterone levels are lowest in the 1-2 implantation group. In the ovariectomized rats there was a stepwise decline in serum leptin (p < 0.05) as the dose of progesterone increased (p < 0.01). Both of these studies suggest that progesterone suppressed maternal serum leptin levels. CONCLUSIONS Increasing placental mass is not associated with increasing maternal serum leptin levels in the pregnant rat; the contrary condition is observed with the least placental implants having the highest leptin levels. Progesterone seems to suppress serum leptin levels in several physiological models.
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Affiliation(s)
| | - Colin Hirst
- Department of Biological Sciences, Union College, Schenectady, NY, USA
- Heart Lung Vascular Institute, University of Tennessee Medical Center, Knoxville, TN, 37920, USA
| | - V Daniel Castracane
- Department of Obstetrics and Gynecology, Texas Tech University Health Sciences Center at the Permian Basin, Odessa, TX, USA.
- Department of Obstetrics and Gynecology, Texas Tech University Health Sciences Center, Amarillo, TX, USA.
- Texas Tech University Health Sciences Center, Lubbock, TX, USA.
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Yu H, Thompson Z, Kiran S, Jones GL, Mundada L, Rubinstein M, Low MJ. Expression of a hypomorphic Pomc allele alters leptin dynamics during late pregnancy. J Endocrinol 2020; 245:115-127. [PMID: 32027603 DOI: 10.1530/joe-19-0576] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 02/06/2020] [Indexed: 12/11/2022]
Abstract
Proopiomelanocortin (POMC) neurons in the hypothalamic arcuate nucleus (ARC) are essential for normal energy homeostasis. Maximal ARC Pomc transcription is dependent on neuronal Pomc enhancer 1 (nPE1), located 12 kb upstream from the promoter. Selective deletion of nPE1 in mice decreases ARC Pomc expression by 70%, sufficient to induce mild obesity. Because nPE1 is located exclusively in the genomes of placental mammals, we questioned whether its hypomorphic mutation would also alter placental Pomc expression and the metabolic adaptations associated with pregnancy and lactation. We assessed placental development, pup growth, circulating leptin and expression of Pomc, Agrp and alternatively spliced leptin receptor (LepR) isoforms in the ARC and placenta of Pomc∆1/∆1 and Pomc+/+ dams. Despite indistinguishable body weights, lean mass, food intake, placental histology and Pomc expression and overall pregnancy outcomes between the genotypes, Pomc ∆1/∆1 females had increased pre-pregnancy fat mass that paradoxically decreased to control levels by parturition. However, Pomc∆1/∆1 dams had exaggerated increases in circulating leptin, up to twice of that of the typically elevated levels in Pomc+/+ mice at the end of pregnancy, despite their equivalent fat mass. Pomc∆1/∆1dams also had increased placental expression of soluble leptin receptor (LepRe), although the protein levels of LEPRE in circulation were the same as Pomc+/+ controls. Together, these data suggest that the hypomorphic Pomc∆1/∆1 allele is responsible for the perinatal super hyperleptinemia of Pomc∆1/∆1 dams, possibly due to upregulated leptin secretion from individual adipocytes.
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Affiliation(s)
- Hui Yu
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Zoe Thompson
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Sylee Kiran
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA.,School of Literature, Science, and Arts, University of Michigan, Ann Arbor, Michigan, USA
| | - Graham L Jones
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA.,Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan, USA
| | - Lakshmi Mundada
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
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- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Marcelo Rubinstein
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA.,Instituto de Investigaciones en Ingeniería Genética y Biología Molecular Consejo Nacional de Investigaciones Científicas y Técnicas and Facultad de Ciencias Exactas y Naturales, Universidad de Buenos, Buenos Aires, Argentina
| | - Malcolm J Low
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
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Khant Aung Z, Grattan DR, Ladyman SR. Pregnancy-induced adaptation of central sensitivity to leptin and insulin. Mol Cell Endocrinol 2020; 516:110933. [PMID: 32707081 DOI: 10.1016/j.mce.2020.110933] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 06/22/2020] [Accepted: 06/29/2020] [Indexed: 02/07/2023]
Abstract
Pregnancy is a time of increased food intake and fat deposition in the mother, and adaptations of glucose homeostasis to meet the energy demands of the growing fetus. As part of these adaptations, leptin and insulin concentrations increase in the maternal circulation during pregnancy. Central effects of leptin and insulin, however, are counterproductive to pregnancy, as increased action of these hormones in the brain lead to suppression of food intake. To prevent this, it is well documented that pregnancy induces a state of leptin- and insulin-insensitivity in the brain, particularly the hypothalamus, in a range of species. While the mechanisms underlying leptin- or insulin-insensitivity during pregnancy vary between species, there is evidence of reduced transport into the brain, impaired activation of intracellular signalling pathways, including reduced leptin receptor expression, and attenuated activation of downstream neuronal pathways, especially for leptin insensitivity. Pregnancy-induced changes in prolactin, growth hormone and leptin are discussed in terms of their role in mediating this reduced response to leptin and insulin.
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Affiliation(s)
- Z Khant Aung
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, 9016, New Zealand
| | - D R Grattan
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, 9016, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, 1010, New Zealand
| | - S R Ladyman
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, 9016, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, 1010, New Zealand.
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7
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Troisi A, Cardinali L, Menchetti L, Speranza R, Verstegen JP, Polisca A. Serum concentrations of leptin in pregnant and non-pregnant bitches. Reprod Domest Anim 2020; 55:454-459. [PMID: 31957075 DOI: 10.1111/rda.13637] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 01/11/2020] [Indexed: 12/18/2022]
Abstract
Leptin regulates body weight and several physiological processes including reproduction. We evaluated the circulating levels of leptin in pregnant and non-pregnant bitches as well as their correlation with body weight, food intake and number of foetuses. Nineteen healthy German shepherd bitches were used and divided in two groups (pregnant n = 12 and non-pregnant n = 7). Blood samples were collected every 15 days starting from ovulation (Day 0) throughout pregnancy (pregnant group, P) or throughout luteal phase (non-pregnant group, NP) In pregnant bitches, leptin concentrations increased from the day of ovulation (1.32 ± 0.06 ng/ml) up to day 45 (1.51 ± 0.06 ng/ml; p < .01) and returned to baseline values from day 60 post-ovulation. In non-pregnant bitches, leptin concentrations remained constant throughout the whole observation period (estimated marginal mean ± SE=1.33 ± 0.38 ng/ml). Pairwise comparisons showed significant differences between P and NP at day 45 post-ovulation (p < .05). Multivariable models indicated that, controlling for time and litter size, there was a positive relationship between leptin concentration and BW (p < .05) although Pearson coefficients showed that the correlation between BW and leptin was only significant in NP animals at day 45 (r = 0.76, p < .05). The multivariable approach also suggested that, holding BW and time constant, leptin concentrations tend to increase as the number of puppies increased (p = .06). Our study supports indirectly the contribution of the feto-placental unit to the circulating maternal leptin concentration.
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Affiliation(s)
- Alessandro Troisi
- Department of Veterinary Medicine, University of Perugia, Perugia, Italy
| | - Lucia Cardinali
- Department of Veterinary Medicine, University of Perugia, Perugia, Italy
| | - Laura Menchetti
- Department of Veterinary Medicine, University of Perugia, Perugia, Italy
| | - Roberto Speranza
- Corso Allevamento e Addestramento Cinofili, Castiglione del Lago (PG), Italy
| | - John P Verstegen
- TherioExpert and Veterinary College University of Nottingham, Nottingham, UK
| | - Angela Polisca
- Department of Veterinary Medicine, University of Perugia, Perugia, Italy
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Gustafson P, Ladyman SR, Brown RSE. Suppression of Leptin Transport Into the Brain Contributes to Leptin Resistance During Pregnancy in the Mouse. Endocrinology 2019; 160:880-890. [PMID: 30840056 DOI: 10.1210/en.2018-01065] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Accepted: 02/27/2019] [Indexed: 11/19/2022]
Abstract
During pregnancy, when both food intake and circulating leptin concentrations increase, the brain becomes insensitive to leptin. The mechanism by which central leptin resistance during pregnancy emerges remains poorly understood. We investigated whether structural changes in the blood-brain barrier (BBB) or changes in carrier-mediated transport of leptin into the brain might contribute to pregnancy-induced leptin resistance. Immunohistochemical evaluation of the BBB at the level of the arcuate nucleus and median eminence in virgin, pregnant, and lactating mice was undertaken by labeling for tanycytes (vimentin), tight junction protein (zona occludens-1), and a marker of fenestrated endothelial capillaries (MECA-32). There were no changes in these BBB markers between virgin, pregnant or lactating mice. Transport of iodine 125-labeled leptin from the peripheral circulation into the brain was completely suppressed during pregnancy, however (days 14 through 16), compared with virgin and lactating (days 7 through 11) mice. This was accompanied by a suppression of leptin clearance from the blood in pregnant mice. We also investigated in virgin mice whether competition with other hormones for transport might contribute to suppression of leptin transport into the brain. Although leptin was able to compete with prolactin transport into the brain, prolactin did not compete with leptin transport. These data demonstrate that suppression of the transport of leptin into the brain during pregnancy, in the absence of structural changes in the BBB, is an important contributor to the insensitivity of the hypothalamus to leptin at this time.
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Affiliation(s)
- Papillon Gustafson
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Sharon R Ladyman
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, New Zealand
| | - Rosemary S E Brown
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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Szczesna M, Kirsz K, Misztal T, Molik E, Zieba DA. The effects of leptin on plasma concentrations of prolactin, growth hormone, and melatonin vary depending on the stage of pregnancy in sheep. J Anim Sci 2018; 96:3348-3357. [PMID: 29788119 DOI: 10.1093/jas/sky203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 05/15/2018] [Indexed: 01/24/2023] Open
Abstract
The effects of hyperleptinemia and leptin resistance during gestation are unclear. Leptin, an important neuroendocrine regulator, has anorexic effects, but its interactions with other metabolic hormones during pregnancy are unclear. We examined potential roles of leptin in regulating prolactin (PRL), GH, and melatonin plasma concentrations during pregnancy in Polish Longwool ewes. Twelve estrus-synchronized ewes carrying twins after mating were randomly assigned to receive i.v. injections of saline or recombinant ovine leptin (2.5 or 5.0 µg/kg BW). Blood samples were collected (15-min intervals over 4 h) immediately before the first injection at dusk and kept under red light. Treatments were repeated at 2-wk intervals, starting before mating and continuing from days 30 to 135 of gestation. Concentrations of plasma PRL, GH, and melatonin were determined using a validated RIA. The effects of leptin on hormone plasma concentrations varied depending on pregnancy stage and leptin dose. PRL plasma concentrations were affected at most stages of pregnancy and before gestation. In non-, very early- (day 30), and late- (day 120 and 135) pregnant ewes, exogenous leptin stimulated PRL (P < 0.001) plasma concentrations, while during the second month of gestation, it decreased PRL concentrations (P < 0.01). Leptin affected GH plasma concentrations (P < 0.05) only during the first 2 mo of pregnancy, with no effects during the second part of gestation or before pregnancy. In early-pregnant ewes (day 30 and 45), leptin decreased melatonin plasma concentrations (P < 0.05), but at day 60, leptin stimulated melatonin plasma concentrations at low (P < 0.01) and high doses (P < 0.05), with no effects in ewes after 105 d of gestation. These data indicate specific pregnancy-induced endocrine adaptations to changes in energy homeostasis, supporting the hypothesis that leptin affects PRL, GH, and melatonin release during gestation.
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Affiliation(s)
- Malgorzata Szczesna
- Agricultural University, Faculty of Animal Sciences, Department of Animal Biotechnology, Krakow, Poland
| | - Katarzyna Kirsz
- Agricultural University, Faculty of Animal Sciences, Department of Animal Biotechnology, Krakow, Poland
| | - Tomasz Misztal
- The Kielanowski Institute of Animal Physiology and Nutrition, Department of Animal Physiology, Polish Academy of Sciences, Jablonna, Poland
| | - Edyta Molik
- Agricultural University, Faculty of Animal Sciences, Department of Animal Biotechnology, Krakow, Poland
| | - Dorota A Zieba
- Agricultural University, Faculty of Animal Sciences, Department of Animal Biotechnology, Krakow, Poland
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10
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Vargas VE, Landeros RV, Lopez GE, Zheng J, Magness RR. Uterine artery leptin receptors during the ovarian cycle and pregnancy regulate angiogenesis in ovine uterine artery endothelial cells†. Biol Reprod 2017; 96:866-876. [PMID: 28339937 PMCID: PMC5819836 DOI: 10.1093/biolre/iox008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 01/31/2017] [Accepted: 02/27/2017] [Indexed: 12/12/2022] Open
Abstract
Leptin regulates body weight, reproductive functions, blood pressure, endothelial function, and fetoplacental angiogenesis. Compared to the luteal phase, the follicular phase and pregnancy are physiological states of elevated estrogen, angiogenesis, and uterine blood flow (UBF). Little is known concerning regulation of uterine artery (UA) angiogenesis by leptin and its receptors. We hypothesized that (1) ex vivo expression of leptin receptors (LEPR) in UA endothelium (UAendo) and UA vascular smooth muscle (UAvsm) is elevated in pregnant versus nonpregnant (Luteal and Follicular) sheep; (2) in vitro leptin treatments differentially modulate mitogenesis in uterine artery endothelial cells from pregnant (P-UAECs) more than in nonpregnant (NP-UAECs) ewes; and (3) LEPR are upregulated in P-UAECs versus NP-UAECs in association with leptin activation of phospho-STAT3 signaling. Local UA adaptations were evaluated using a unilateral pregnant sheep model where prebreeding uterine horn isolation (nongravid) restricted gravidity to one horn. Immunolocalization revealed LEPR in UAendo and UAvsm from pregnant and nonpregnant sheep. Contrary to our hypothesis, western analysis revealed that follicular UAendo and UAvsm LEPR were greater than luteal, nongravid, gravid, and control pregnant. Compared to pregnant groups, LEPR were elevated in renal artery endothelium of follicular and luteal sheep. Leptin treatment significantly increased mitogenesis in follicular phase NP-UAECs and P-UAECs, but not luteal phase NP-UAECs. Although UAEC expression of LEPR was similar between groups, leptin treatment only activated phospho-STAT3 in follicular NP-UAECs and P-UAECs. Thus, leptin may play an angiogenic role particularly in preparation for the increased UBF during the periovulatory period and subsequently to meet the demands of the growing fetus.
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Affiliation(s)
- Vladimir E. Vargas
- Department of Ob/Gyn, University of Wisconsin, Madison, Wisconsin, USA
- Department of Ob/Gyn, Perinatal Research Vascular Center, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | | | - Gladys E. Lopez
- Department of Ob/Gyn, University of Wisconsin, Madison, Wisconsin, USA
| | - Jing Zheng
- Department of Ob/Gyn, University of Wisconsin, Madison, Wisconsin, USA
| | - Ronald R. Magness
- Department of Ob/Gyn, University of Wisconsin, Madison, Wisconsin, USA
- Department of Ob/Gyn, Perinatal Research Vascular Center, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
- Department of Pediatrics, University of Wisconsin, Madison, Wisconsin, USA
- Department of Animal Sciences, University of Wisconsin, Madison, Wisconsin, USA
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11
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Ilekis JV, Tsilou E, Fisher S, Abrahams VM, Soares MJ, Cross JC, Zamudio S, Illsley NP, Myatt L, Colvis C, Costantine MM, Haas DM, Sadovsky Y, Weiner C, Rytting E, Bidwell G. Placental origins of adverse pregnancy outcomes: potential molecular targets: an Executive Workshop Summary of the Eunice Kennedy Shriver National Institute of Child Health and Human Development. Am J Obstet Gynecol 2016; 215:S1-S46. [PMID: 26972897 DOI: 10.1016/j.ajog.2016.03.001] [Citation(s) in RCA: 179] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 02/11/2016] [Accepted: 03/01/2016] [Indexed: 12/26/2022]
Abstract
Although much progress is being made in understanding the molecular pathways in the placenta that are involved in the pathophysiology of pregnancy-related disorders, a significant gap exists in the utilization of this information for the development of new drug therapies to improve pregnancy outcome. On March 5-6, 2015, the Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health sponsored a 2-day workshop titled Placental Origins of Adverse Pregnancy Outcomes: Potential Molecular Targets to begin to address this gap. Particular emphasis was given to the identification of important molecular pathways that could serve as drug targets and the advantages and disadvantages of targeting these particular pathways. This article is a summary of the proceedings of that workshop. A broad number of topics were covered that ranged from basic placental biology to clinical trials. This included research in the basic biology of placentation, such as trophoblast migration and spiral artery remodeling, and trophoblast sensing and response to infectious and noninfectious agents. Research findings in these areas will be critical for the formulation of the development of future treatments and the development of therapies for the prevention of a number of pregnancy disorders of placental origin that include preeclampsia, fetal growth restriction, and uterine inflammation. Research was also presented that summarized ongoing clinical efforts in the United States and in Europe that has tested novel interventions for preeclampsia and fetal growth restriction, including agents such as oral arginine supplementation, sildenafil, pravastatin, gene therapy with virally delivered vascular endothelial growth factor, and oxygen supplementation therapy. Strategies were also proposed to improve fetal growth by the enhancement of nutrient transport to the fetus by modulation of their placental transporters and the targeting of placental mitochondrial dysfunction and oxidative stress to improve placental health. The roles of microRNAs and placental-derived exosomes, as well as messenger RNAs, were also discussed in the context of their use for diagnostics and as drug targets. The workshop discussed the aspect of safety and pharmacokinetic profiles of potential existing and new therapeutics that will need to be determined, especially in the context of the unique pharmacokinetic properties of pregnancy and the hurdles and pitfalls of the translation of research findings into practice. The workshop also discussed novel methods of drug delivery and targeting during pregnancy with the use of macromolecular carriers, such as nanoparticles and biopolymers, to minimize placental drug transfer and hence fetal drug exposure. In closing, a major theme that developed from the workshop was that the scientific community must change their thinking of the pregnant woman and her fetus as a vulnerable patient population for which drug development should be avoided, but rather be thought of as a deprived population in need of more effective therapeutic interventions.
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Affiliation(s)
- John V Ilekis
- Pregnancy and Perinatology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Department of Health and Human Services, Bethesda, MD.
| | - Ekaterini Tsilou
- Obstetric and Pediatric Pharmacology and Therapeutics Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Department of Health and Human Services, Bethesda, MD.
| | - Susan Fisher
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California San Francisco, San Francisco, CA
| | - Vikki M Abrahams
- Obstetrics, Gynecology and Reproductive Sciences, Yale School of Medicine; New Haven, CT
| | - Michael J Soares
- Institute of Reproductive Health and Regenerative Medicine and Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, KS
| | - James C Cross
- Comparative Biology and Experimental Medicine, University of Calgary Health Sciences Centre, Calgary, Alberta, Canada
| | - Stacy Zamudio
- Department of Obstetrics and Gynecology, Hackensack University Medical Center, Hackensack, NJ
| | - Nicholas P Illsley
- Department of Obstetrics and Gynecology, Hackensack University Medical Center, Hackensack, NJ
| | - Leslie Myatt
- Center for Pregnancy and Newborn Research, University of Texas Health Science Center, San Antonio, TX
| | - Christine Colvis
- Therapeutics Discovery Program, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD
| | - Maged M Costantine
- Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, TX
| | - David M Haas
- Department of Obstetrics and Gynecology Indiana University, Indianapolis, IN
| | | | - Carl Weiner
- University of Kansas Medical Center, Kansas City, KS
| | - Erik Rytting
- Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, TX
| | - Gene Bidwell
- Department of Neurology, University of Mississippi Medical Center, Jackson, MS
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12
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Szczesna M, Zieba DA. Phenomenon of leptin resistance in seasonal animals: the failure of leptin action in the brain. Domest Anim Endocrinol 2015; 52:60-70. [PMID: 25863197 DOI: 10.1016/j.domaniend.2015.03.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 03/08/2015] [Accepted: 03/08/2015] [Indexed: 10/23/2022]
Abstract
The core of the leptin resistance hypothesis promulgated several years ago to explain obesity as a result of environmental causes consists of 2 tenets: the extinction of leptin-induced intracellular signaling downstream of leptin binding to the long form of the neuronal receptor LTRb in the hypothalamus and the impedance to leptin entry imposed at the blood-brain barrier (BBB). A recent comprehensive investigation concluded that a central leptin insufficiency associated with obesity can be attributed to a decreased efficiency of BBB leptin transport and not to leptin insensitivity within the hypothalamus. Interestingly, anorectic leptin's effects are counteracted in some individuals by a natural resistance associated with hyperleptinemia, which is related to changes in hypothalamic sensitivity to leptin (eg, due to malnutrition, obesity, or seasonal variations due to day-length-dependent reproduction changes). In sheep, it has been observed that the hypothalamus is resistant to leptin in some periods, which is related to the adaptation of these animals to annual changes in energy supply and demand. However, a broad range of ambiguities exists regarding the implications that the intracellular signaling of signal transducer and activator of transcription-2/suppressor of cytokine signaling 3 (STAT2/SOCS3) imparts central leptin resistance. Furthermore, several plausible alternative possibilities have been proposed, such as compensatory functional and anatomic reorganizations in the appetite regulating network, rearrangements in the afferent hormonal feedback signaling involved in weight homeostasis, and modifications in leptin transport to the hypothalamus across the BBB. Taken together, these observations suggest that the contention that impaired intracellular signaling downstream of leptin entry into the appetite regulating network expedites environmentally induced obesity remains unsubstantiated and requires further evidence. Furthermore, pregnancy decreases hypothalamic sensitivity to leptin (or other unknown mechanisms), and lactation can also alter the appetite-suppressing central activity of leptin. The objective of this review was to offer an approach to understanding (1) how information regarding nutritional status is transmitted to and interpreted within the hypothalamus in animals, with special attention on seasonally breeding animals and (2) whether central leptin resistance and/or leptin insufficiency in the hypothalamus favors the development of obesity.
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Affiliation(s)
- M Szczesna
- Department of Animal Biotechnology, Agricultural University in Krakow, 31-248 Krakow, Poland
| | - D A Zieba
- Department of Animal Biotechnology, Agricultural University in Krakow, 31-248 Krakow, Poland.
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Serum leptin as an indicator of fat levels in white-tailed deer (Odocoileus virginianus) in the southeastern USA. J Wildl Dis 2014; 50:887-90. [PMID: 24949928 DOI: 10.7589/2013-08-223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Leptin is a hormone that plays a key role in regulating energy intake, appetite, and metabolism. In some mammals, leptin has been shown to circulate at levels proportional to body fat, which could make it useful for nonlethal evaluation of body condition. Leptin's usefulness for estimating fat levels (i.e., body condition) of white-tailed deer (Odocoileus virginianus) is unknown. We quantified serum leptin concentrations in a sample of free-ranging, female deer collected in July 2008 and March 2009 from coastal North Carolina, USA. We compared leptin concentrations with kidney fat index, femur marrow fat index, and kidney fat mass. Additionally, we assessed differences in leptin concentrations between the two seasons, lactating and nonlactating females, and gestating and nongestating females. Leptin concentrations were similar between seasons but were lower in lactating and gestating females. We did not detect significant relationships between leptin and the body fat metrics, indicating that leptin may have limited value for estimating fat reserves in white-tailed deer.
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Herrid M, Palanisamy SKA, Ciller UA, Fan R, Moens P, Smart NA, McFarlane JR. An updated view of leptin on implantation and pregnancy: a review. Physiol Res 2014; 63:543-57. [PMID: 24908087 DOI: 10.33549/physiolres.932674] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The hormone leptin, which is thought to be primarily produced by adipose tissue, is a polypeptide that was initially characterized by its ability to regulate food intake and energy metabolism. Leptin appears to signal the status of body energy stores to the brain, resulting in the regulation of food intake and whole-body energy expenditure. Subsequently, it was recognized as a cytokine with a wide range of peripheral actions and is involved in the regulation of a number of physiological systems including reproduction. In the fed state, leptin circulates in the plasma in proportion to body adiposity in all species studied to date. However other factors such as sex, age, body mass index (BMI), sex steroids and pregnancy may also affect leptin levels in plasma. In pregnant mice and humans, the placenta is also a major site of leptin expression. Leptin circulates in biological fluids both as free protein and in a form that is bound to the soluble isoform of its receptor or other binding proteins such as one of the immunoglobulin superfamily members Siglec-6 (OB-BP1). Although the actions of leptin in the control of reproductive function are thought to be exerted mainly via the hypothalamic-pituitary-gonadal axis, there have also been reports of local direct effects of leptin at the peripheral level, however, these data appear contradictory. Therefore, there is a need to summarize the current status of research outcomes and analyze the possible reasons for differing results and thus provide researchers with new insight in designing experiments to investigate leptin effect on reproduction. Most importantly, our recent experimental data suggesting that reproductive performance is improved by decreasing concentrations of peripheral leptin was unexpected and cannot be explained by hypotheses drawn from the experiments of excessive exogenous leptin administration to normal animals or ob/ob mice.
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Affiliation(s)
- M Herrid
- University of New England, Armidale, Australia.
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15
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Wang H, Fu J, Wang A. Expression of obesity gene and obesity gene long form receptor in endometrium of Yorkshire sows during embryo implantation. Mol Biol Rep 2014; 41:1597-606. [PMID: 24407604 DOI: 10.1007/s11033-013-3006-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 12/30/2013] [Indexed: 10/25/2022]
Abstract
There is accumulating evidence that leptin may be directly involved in mammalian reproduction, however, the potential role of obesity gene/obesity gene long form receptor (ob/ob-Rb) system in porcine implantation is poorly understood. To further confirm this role, mRNA and protein expression of ob/ob-Rb in implantation site and inter-implantation sites of porcine uterus on pregnancy day 13, 18 and 24 were compared in this study. Ob mRNA level went up with the advance of pregnancy and was higher in implantation site than inter-implantation site (P < 0.05). But ob-Rb mRNA, which was negative-regulated by leptin, went down with the advance of pregnancy and lessened in implantation site compared with inter-implantation site (P < 0.05). During the three implantation phase, leptin protein peaked at day 18 pregnancy (P < 0.05) and leptin protein at implantation site were always higher than inter-implantation site (P < 0.05). The higher ob-Rb protein in implantation site compared with inter-implantation site (P < 0.05) only appeared at day 18 pregnancy. Localization of ob/ob-Rb protein in porcine uterus was assayed using immunohistochemistry and found that ob/ob-Rb protein mainly located in luminal epithelium and glandular epithelium in pregnant pigs, but distinct immune-staining of leptin also detected in stroma in non-pregnancy porcine uterus except for luminal epithelium and glandular epithelium. In conclusion, the peak of leptin and the peak of ob-Rb protein in implantation site specifically appeared on day 18 pregnancy of pig. Another funning discovery is ob-Rb mRNA in porcine endometrium was mainly negative-regulated by leptin. The space-time difference of gene and protein expression for ob/ob-Rb confirmed ob/ob-Rb system role as delicate regulator of porcine implantation process.
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Affiliation(s)
- Hongfang Wang
- National Engineering Laboratory for Animal Breeding & Key Laboratory of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, China Agricultural University, 100193, Beijing, People's Republic of China
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16
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Page-Wilson G, Reitman-Ivashkov E, Meece K, White A, Rosenbaum M, Smiley RM, Wardlaw SL. Cerebrospinal fluid levels of leptin, proopiomelanocortin, and agouti-related protein in human pregnancy: evidence for leptin resistance. J Clin Endocrinol Metab 2013; 98:264-71. [PMID: 23118421 PMCID: PMC3537103 DOI: 10.1210/jc.2012-2309] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Leptin suppresses appetite by modulating the expression of hypothalamic neuropeptides including proopiomelanocortin (POMC) and agouti-related peptide (AgRP). Yet during pregnancy, caloric consumption increases despite elevated plasma leptin levels. DESIGN AND PARTICIPANTS To investigate this paradox, we measured leptin and soluble leptin receptor in plasma and leptin, POMC, and AgRP in cerebrospinal fluid (CSF) from 21 fasting pregnant women before delivery by cesarean section at a university hospital and from 14 fasting nonpregnant women. RESULTS Prepregnancy body mass index was 24.6 ± 1.1 (SE) vs. 31.3 ± 1.3 at term vs. 26.5 ± 1.6 kg/m(2) in controls. Plasma leptin (32.9 ± 4.6 vs. 16.7 ± 3.0 ng/ml) and soluble leptin receptor (30.9 ± 2.3 vs. 22.1 ± 1.4 ng/ml) levels were significantly higher in pregnant women. However, mean CSF leptin did not differ between the two groups (283 ± 34 vs. 311 ± 32 pg/ml), consistent with a relative decrease in leptin transport into CSF during pregnancy. Accordingly, the CSF/plasma leptin percentage was 1.0 ± 0.01% in pregnant subjects vs. 2.1 ± 0.2% in controls (P < 0.0001). Mean CSF AgRP was significantly higher in pregnant subjects (32.3 ± 2.7 vs. 23.5 ± 2.5 pg/ml; P = 0.03). Mean CSF POMC was not significantly different in pregnant subjects (200 ± 13.6 vs. 229 ± 17.3 fmol/ml; P = 0.190). However, the mean AgRP/POMC ratio was significantly higher among pregnant women (P = 0.003), consistent with an overall decrease in melanocortin tone favoring increased food intake during pregnancy. CONCLUSIONS These data demonstrate that despite peripheral hyperleptinemia, positive energy balance is achieved during pregnancy by a relative decrease in central leptin concentrations and resistance to leptin's effects on target neuropeptides that regulate energy balance.
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Ladyman SR, Fieldwick DM, Grattan DR. Suppression of leptin-induced hypothalamic JAK/STAT signalling and feeding response during pregnancy in the mouse. Reproduction 2012; 144:83-90. [DOI: 10.1530/rep-12-0112] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Hyperphagia during pregnancy, despite rising concentrations of the satiety hormone leptin, suggests that a state of leptin resistance develops. This study investigated the satiety response and hypothalamic responses to leptin during pregnancy in the mouse. Pregnant (day 13) and nonpregnant mice received an i.p. injection of either leptin or vehicle and then 24-h food intake was measured. Further groups of pregnant and nonpregnant mice were perfused 2 h after leptin or vehicle injections and brains were processed for pSTAT3 and pSTAT5 immunohistochemistry. Leptin treatment significantly decreased food intake in nonpregnant mice. In pregnant mice, however, leptin treatment did not suppress food intake, indicating a state of leptin resistance. In the arcuate nucleus, leptin treatment increased the number of cells positive for pSTAT3, a marker of leptin activity, to a similar degree in both nonpregnant and pregnant mice. In the ventromedial nucleus (VMN), the leptin-induced increase in pSTAT3-positive cell number was significantly reduced in pregnant mice compared to that in nonpregnant mice. In nonpregnant mice, leptin treatment had no effect on the number of pSTAT5-positive cells, suggesting that in this animal model, leptin does not act through STAT5. In pregnant mice, basal levels of pSTAT5 were higher than in nonpregnant mice, and leptin treatment led to a decrease in the number of pSTAT5-positive cells in the hypothalamus. Overall, these results demonstrate that during pregnancy in the mouse, a state of leptin resistance develops, and this is associated with a reduced sensitivity of the VMN to leptin.
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Schlitt JM, Schulz LC. The source of leptin, but not leptin depletion in response to food restriction, changes during early pregnancy in mice. Endocrine 2012; 41:227-35. [PMID: 22042484 PMCID: PMC3291745 DOI: 10.1007/s12020-011-9548-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 10/14/2011] [Indexed: 12/21/2022]
Abstract
Maternal food restriction during pregnancy results in adverse consequences for offspring, including obesity and cardiovascular disease. Early pregnancy is a critical period for this programming effect. Leptin is a regulator of energy homeostasis that also affects placental and fetal development. As food restriction results in decreased serum leptin levels, at least in non-pregnant animals, leptin depletion may be one mechanism by which food restriction affects development. The objective of this study was to test whether moderate food restriction affects serum leptin concentrations during the first half of pregnancy. We found that restriction to 50% of ad libitum consumption levels resulted in a significant decrease in serum leptin concentrations in both pregnant and non-pregnant female mice. There was no significant difference in serum leptin concentrations between non-pregnant females and at pregnancy day 11.5 when fed ad libitum. However, there was a difference in the source of leptin during pregnancy, with greater production in visceral fat in pregnant mice, and greater production in subcutaneous fat in non-pregnant mice. Leptin concentrations were dependent on time of day and time of sampling relative to feeding, particularly in restricted mice. There was a significant difference in serum leptin concentrations between fed and restricted mice when they were fed and sampled in afternoon, but not when they were fed and sampled in morning. We conclude that food restriction results in a significant decrease in leptin concentration during the first half of pregnancy in mice, but that detection of this relationship is subject to experimental design considerations.
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Affiliation(s)
| | - Laura C. Schulz
- Corresponding author ADDRESS: Dept. of Obstetrics, Gynecology and Women’s Health, University of Missouri, N625 Health Sciences Center, 1 Hospital Drive, Columbia, MO 65212, , Phone: (573)-884-1408, Fax (573)882-9010
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D'Ippolito S, Tersigni C, Scambia G, Di Simone N. Adipokines, an adipose tissue and placental product with biological functions during pregnancy. Biofactors 2012; 38:14-23. [PMID: 22287297 DOI: 10.1002/biof.201] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Accepted: 12/28/2011] [Indexed: 01/03/2023]
Abstract
Latter half of pregnancy is characterized by a "physiological diabetogenic state" since changes in insulin-sensitivity have been well documented. These changes ensure continuous supply of nutrients to the growing fetus. In the last years the role of adipocyte-derived signaling molecules, collectively known as adipokines has been object of different in vitro and in vivo studies. Of interest, adipokines and/or their receptors are expressed in the placental tissue which, therefore, can contribute to development of maternal insulin-resistance and, as a consequence, fetal growth. Leptin, adiponectin, and resistin represent the most well studied adipokines and, with the exception of adiponectin, their serum and placental levels increase as pregnancy progresses. High levels of adipokines have also been detected in umbilical plasma hence suggesting a possible role on fetal development and metabolism; however, it remains still unclear if such adipokines can directly stimulate fetal tissues development acting as growth factors. In addition to their well known metabolic effects, we also reported studies describing the role of adipokines in promoting proliferation and invasiveness of trophoblast cells and affecting local angiogenic processes. These observations strongly suggest that adipokines, by alternatively interfering with placental development, may affect pregnancy outcome and fetal growth. However, further studies are needed to better understand the local regulation of their expression. © 2012 International Union of Biochemistry and Molecular Biology, Inc.
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Affiliation(s)
- Silvia D'Ippolito
- Department of Obstetrics and Gynecology, Policlinico A. Gemelli, Università Cattolica del Sacro Cuore, Rome, Italy
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20
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Detection of Leptin Activity in Living Cells Expressing Chicken Leptin Receptor and STAT3. J Poult Sci 2012. [DOI: 10.2141/jpsa.011085] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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21
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Otvos L, Shao WH, Vanniasinghe AS, Amon MA, Holub MC, Kovalszky I, Wade JD, Doll M, Cohen PL, Manolios N, Surmacz E. Toward understanding the role of leptin and leptin receptor antagonism in preclinical models of rheumatoid arthritis. Peptides 2011; 32:1567-74. [PMID: 21723351 DOI: 10.1016/j.peptides.2011.06.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Revised: 06/16/2011] [Accepted: 06/16/2011] [Indexed: 01/20/2023]
Abstract
A potential link between obesity, circulating leptin levels and autoimmune disease symptoms suggests that targeting the leptin receptor (ObR) might be a viable novel strategy to combat rheumatoid arthritis (RA). However, studies in animal models and evaluation of clinical cases did not provide clear view on leptin's involvement in RA. To validate ObR as RA target, we used our peptide-based ObR agonists and antagonist in different in vitro and in vivo models of the disease. In human peripheral blood mononuclear cells, leptin and its agonist fragment, desI(2)-E1/Aca, moderately induced constitutive activation of a major proinflammatory transcription factor, NF-κB, while the ObR antagonist peptide Allo-aca inhibited the process. Leptin administration itself did not induce arthritis in rats, but worsened the clinical condition of mice given K/BxN serum transfer arthritis. Simultaneous administration of Allo-aca reduced leptin-dependent increase in disease severity by more than 50%, but the antagonist was ineffective when injected with a 3-day delay. In rats inflicted with mild adjuvant-induced arthritis, both leptin and Allo-aca reduced the extent of joint swelling and the number of arthritic joints. In a more aggressive disease stage, Allo-aca decreased the number of arthritic joints in a dose-dependent manner but did not affect other arthritis markers. In summary, leptin exerts diverse effects on RA depending on the experimental model. This might reflect the heterogeneous character of RA, which is differently impacted by leptin and is unmasked by ObR antagonism. Nevertheless, the results suggest that ObR antagonists might become useful therapeutics in leptin-sensitive early stages of RA.
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Affiliation(s)
- Laszlo Otvos
- Department of Biology, Temple University, Philadelphia, PA 19122, USA.
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22
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Zhang XY, Jing BB, Wang DH. Cold exposure does not decrease serum leptin concentration, but increases energy intake and thermogenic capacity in pregnant Brandt's voles (Lasiopodomys brandtii). ZOOLOGY 2009; 112:206-16. [DOI: 10.1016/j.zool.2008.09.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Revised: 08/21/2008] [Accepted: 09/03/2008] [Indexed: 01/24/2023]
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Jelks A, Belkacemi L, Han G, Chong WL, Ross MG, Desai M. Paradoxical increase in maternal plasma leptin levels in food-restricted gestation: contribution by placental and adipose tissue. Reprod Sci 2009; 16:665-75. [PMID: 19372589 DOI: 10.1177/1933719109334257] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Maternal food restriction (FR) during pregnancy results in decreased body weight with increased plasma leptin. To address this paradox, we investigated the effects of FR during pregnancy on growth and leptin levels in maternal, placental, and fetal sites. From embryonic day E10, control pregnant rats received ad libitum (AdLib) food, whereas study rats were 50% FR. At gestational ages, E16 and E20, the alterations in maternal body composition, retroperitoneal versus subcutaneous adipose leptin expression, and plasma leptin levels were studied. Furthermore, these changes were related to non-pregnant (NP) status and placental/fetal growth and leptin levels. As compared to NP, both FR and AdLib dams showed a progressive increase in body and lean body mass. However, total body fat was reduced in FR dams but remained unchanged in AdLib dams. Furthermore, plasma leptin levels in FR dams were markedly increased at E20 unlike AdLib dams, which showed moderate increments at E16 and E20. Additionally, FR dams showed significantly decreased leptin expression in subcutaneous and notably unaltered levels in retroperitoneal adipose tissue, suggesting an alternate source of elevated maternal plasma leptin. More importantly, the FR dams had reduced placental weights with paradoxical increased leptin expression at both gestations. Thus, increased plasma leptin levels at E20 in maternal FR pregnancies may be explained, in part, by upregulation of placental leptin. Despite maternal and placental hyperleptinemia during FR pregnancies, the growth-restricted FR fetus had reduced leptin levels. These findings have important implications for pregnancy outcome and fetal growth.
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Affiliation(s)
- Andrea Jelks
- Department of Obstetrics and Gynecology, Perinatal Research Laboratories, David Geffen School of Medicine, University of California Los Angeles, Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, Torrance, California 90502, USA
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Schulz LC, Widmaier EP, Qiu J, Roberts RM. Effect of leptin on mouse trophoblast giant cells. Biol Reprod 2009; 80:415-24. [PMID: 19038858 PMCID: PMC2805391 DOI: 10.1095/biolreprod.108.073130] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Revised: 09/08/2008] [Accepted: 10/20/2008] [Indexed: 01/29/2023] Open
Abstract
Leptin plays a role in both energy homeostasis and reproduction, and it is required in early pregnancy. It stimulates metalloproteinase activity in cultured human trophoblasts and invasiveness of cultured mouse trophoblasts. Our goal has been to examine mechanisms that underpin the ability of leptin to promote trophoblast invasiveness in primary cultures of mouse trophoblasts. Leptin stimulated the phosphorylation of MEK (MAP2K1) but not signal transducer and activator of transcription 3 (STAT3) in the cultures, increased the concentration of the suppressor of cytokine signaling 3 (SOCS3) protein, and upregulated metalloproteinase activity. Microarray analysis revealed that leptin stimulated select genes with roles in cell motility, including Stmn, a gene linked to invasiveness in other cell types. There was also an increase in activity of several genes associated with MAPK and RhoGTPase signaling. In addition, leptin muted expression of genes correlated with terminal differentiation of trophoblast giant cells, including ones associated with the TGFbeta signaling pathway and endoreduplication of DNA, and upregulated selected prolactin-related family members. Feulgen staining of leptin-treated cells revealed a loss of cells with low ploidy. The data suggest that leptin accelerates disappearance of non-giant cells while inhibiting terminal differentiation of committed giant cells, possibly by maintaining cells in an intermediate stage of differentiation.
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Affiliation(s)
- L C Schulz
- Division of Animal Sciences, University of Missouri, Columbia, Missouri 65211, USA.
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Tauson AH, Forsberg M, Chwalibog A. High leptin in pregnant mink (Mustela vison) may exert anorexigenic effects: a permissive factor for rapid increase in food intake during lactation. Br J Nutr 2007; 91:411-21. [PMID: 15005827 DOI: 10.1079/bjn20041049] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The role for leptin in food intake regulation in the mink, a polytocous seasonal breeder with altricial young, was investigated in pregnant and lactating dams and data were related to quantitative energy metabolism measurements and plasma concentrations of other important metabolic hormones. A total of nine mink dams were measured in consecutive 1-week balance periods, each including a 22h measurement of heat production by means of indirect calorimetry, and blood was sampled at weekly intervals throughout gestation and during lactation weeks 1–4. Intake of metabolisable energy (ME) was high and energy balance was positive until the first third of true gestation. During mid- and late gestation ME intake decreased (P<0·001) while heat production remained almost constant, resulting in negative energy balance and the loss of body weight. From late gestation until lactation week 4, ME intake increased by 3·5 times, but weight loss continued. Plasma concentrations of leptin were approximately doubled during the last two-thirds of true gestation (P<0·01), demonstrating a clear gestational hyperleptinaemia. Concentrations declined rapidly after parturition and then remained stable. Insulin was independent of leptin, with low concentrations coincident with hyperleptinaemia. Also, concentrations of thyroid hormones declined during gestation, probably reflecting the low food intake. Hyperleptinaemia concomitant with low ME intake, negative energy balance and mobilisation of body reserves suggested an anorexigenic effect of leptin in pregnant mink. This suppression of food intake in late gestation might be permissive for the rapid increase in food intake occurring after parturition.
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Affiliation(s)
- Anne-Helene Tauson
- Department of Animal Science and Animal Health, The Royal Veterinary and Agricultural University, Bülowsvej 13, DK-1870 Frederiksberg C, Denmark.
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Schulz LC, Townsend K, Kunz TH, Widmaier EP. Inhibition of trophoblast invasiveness in vitro by immunoneutralization of leptin in the bat, Myotis lucifugus (Chiroptera). Gen Comp Endocrinol 2007; 150:59-65. [PMID: 16938297 DOI: 10.1016/j.ygcen.2006.07.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2006] [Revised: 07/06/2006] [Accepted: 07/13/2006] [Indexed: 10/24/2022]
Abstract
In addition to effects on metabolism and appetite, leptin is a reproductive hormone produced and secreted by the placenta of many, but not all mammalian species. In mice, in which the placenta does not secrete leptin, exogenously added leptin stimulates invasiveness of early (but not late)-gestation trophoblast cells. We report a similar phenomenon occurs in Myotis lucifugus (little brown myotis), a species in which the placenta synthesizes and secretes leptin. Immunoneutralization of endogenously secreted leptin from cultured M. lucifugus trophoblast cells inhibited the ability of these cells to invade a matrigel matrix. The effect was not due to an inhibitory effect of the antibody on cell proliferation, nor was it a non-specific effect of antibody administration. Cell invasion was significantly reduced in untreated cells obtained from late-gestation placentas, and the antibody had no effect at that time. This occurred despite continued expression throughout gestation of the long (OBRb) and short (OBRa) isoforms of leptin receptor mRNA. This study suggests that an important function of leptin during pregnancy is an effect on trophoblast cell invasiveness, at a time when the placenta is becoming established. That this occurs in two phylogenetically unrelated and distant species, regardless of whether the placenta is a source of secreted leptin, suggests that this is a highly conserved reproductive action of leptin.
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Affiliation(s)
- Laura C Schulz
- Department of Biology, Boston University, Boston, MA 02215, USA.
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27
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Herrid M, Nguyen VL, Hinch G, McFarlane JR. Leptin has concentration and stage-dependent effects on embryonic development in vitro. Reproduction 2006; 132:247-56. [PMID: 16885533 DOI: 10.1530/rep.1.01083] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
There is accumulating evidence that leptin may be directly involved in pre-implantation embryonic development, however, it is unclear whether there is a concentration and stage-dependent regulatory pattern. In this study, the addition of 10 ng/ml human recombinant leptin to the culture medium significantly increased the percentage of two-cell mouse embryos that developed into blastocysts and hatched blastocysts, whereas in the presence of 100 ng/ml leptin, the development rate was significantly inhibited. The total cell numbers in the hatched blastocysts were significantly higher in the presence of 10 ng/ml leptin compared with controls and higher concentrations. The differential sensitivity to leptin was found to vary among embryos at different stages of development. Supplementation of leptin (10 ng/ml) to culture medium at two- to eight-cell stages resulted in a consistent stimulatory effect on embryo development. Most interestingly, the inhibitory effect of high leptin concentration (100 ng/ml) on embryo development was diminished when it was added to the culture medium at the eight-cell stage of development. The concentration-dependent regulation pattern was confirmed using sheep embryos, under similar conditions although sheep embryos appeared to be more sensitive in responding to leptin. Having established the effect of exogenous leptin on embryo development, the expression pattern of leptin and its receptors were also investigated. Leptin mRNA was not detected in mouse two-, four-, eight-cell and blastocyst stage embryos, whereas three isoforms of leptin receptor (Ob-Ra, Ob-Rb and Ob-Re) were identified in these cells, indicating that leptin is likely to modulate embryo development via a paracrine signalling system.
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Affiliation(s)
- Muren Herrid
- Animal Physiology, University of New England, Armidale NSW 2350, Australia.
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28
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Kirwin SM, Bhandari V, Dimatteo D, Barone C, Johnson L, Paul S, Spitzer AR, Chander A, Hassink SG, Funanage VL. Leptin enhances lung maturity in the fetal rat. Pediatr Res 2006; 60:200-4. [PMID: 16864704 DOI: 10.1203/01.pdr.0000227478.29271.52] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Pulmonary alveolar type II cells synthesize and secrete phospholipids and surfactant proteins. In most mammalian species, the synthesis of phospholipids and proteins of lung surfactant increases with fetal lung maturation, which occurs late in gestation. Factors that may promote lung maturation and surfactant production include the placental hormone, leptin, whose expression increases with advancing gestational age. We demonstrate that physiologic concentrations of leptin (1 and 10 ng/mL) increase the levels of surfactant proteins (SP) A, B, and C mRNA as well as SP-A and SP-B protein in d-17 fetal rat lung explants in vitro. To determine whether leptin exerts similar effects in vivo, we administered leptin antenatally to pregnant rats and compared its effects to that of dexamethasone, a known mediator of fetal lung development. Antenatal treatment with leptin for 2 d significantly increased the average weight of the fetal lungs in relation to their body weight. Histologic analysis revealed that the increase in fetal lung weight was accompanied by an increase in the number and maturation of type II alveolar cells and the expression of surfactant proteins B and C in these cells. Collectively, these results suggest that leptin is a cytokine regulator of rat fetal lung maturity.
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Affiliation(s)
- Susan M Kirwin
- Department of Biomedical Research and Pediatrics, Alfred I. duPont Hospital for Children/Nemours Children's Clinic, Delaware 19803, USA
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Hauguel-de Mouzon S, Lepercq J, Catalano P. The known and unknown of leptin in pregnancy. Am J Obstet Gynecol 2006; 194:1537-45. [PMID: 16731069 DOI: 10.1016/j.ajog.2005.06.064] [Citation(s) in RCA: 165] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2005] [Revised: 05/16/2005] [Accepted: 06/14/2005] [Indexed: 01/12/2023]
Abstract
Leptin, which was identified originally as an adipocyte-derived protein, was regarded for years as an exclusive regulator of satiety and energy homeostasis. A role for leptin in pregnancy was later suggested by the findings that plasma levels during gestation are greater than in nongravid individuals and that leptin is synthesized within the fetoplacental unit. Observational studies have established that leptin production is dysregulated in several pathologic stages of pregnancy in association with alterations of fetal growth. For example, an overproduction of leptin by the placenta in pregnancy with diabetes mellitus or hypertension is associated with maternal hyperleptinemia. Evidence is also accumulating that umbilical leptin levels can be viewed as a biomarker of fetal adiposity. Ten years after its discovery as a hormone, we review the known and unknowns of leptin in pregnancy with particular emphasis on its functions in health and disease. We aim to demonstrate that studies of leptin in pregnancy largely have contributed to insight into the mechanisms of leptin action, both as a hormone and as a cytokine.
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Abstract
Leptin influences satiety, adiposity, and metabolism and is associated with mechanisms regulating puberty onset, fertility, and pregnancy in various species. Maternal hyperleptinemia is a hallmark of mammalian pregnancy, although both the roles of leptin and the mechanisms regulating its synthesis appear to be taxa specific. In pregnant humans and nonhuman primates, leptin is produced by both maternal and fetal adipose tissues, as well as by the placental trophoblast. Specific receptors in the uterine endometrium, trophoblast, and fetus facilitate direct effects of the polypeptide on implantation, placental endocrine function, and conceptus development. A soluble isoform of the receptor may be responsible for inducing maternal leptin resistance during pregnancy and/or may facilitate the transplacental passage of leptin for the purpose of directly regulating fetal development. The steroid hormones are linked to the regulation of leptin and the leptin receptor and probably interact with other pregnancy-specific, serum-borne factors to regulate leptin dynamics during pregnancy. In addition to its effects on normal conceptus development, leptin is linked to mechanisms affecting a diverse array of pregnancy-specific pathologies that include preeclampsia, gestational diabetes, and intrauterine growth restriction. Association with these anomalies and with mechanisms pointing to a fetal origin for a range of conditions affecting the individual's health in adult life, such as obesity, diabetes mellitus, and cardiovascular disease, reiterate the need for continued research dedicated to elucidating leptin's roles and regulation throughout gestation.
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Affiliation(s)
- Michael C Henson
- Department of Obstetrics and Gynecology, Tulane University Health Sciences Center, New Orleans, Louisiana 70112-2699, USA.
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31
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Makrydimas G, Vandecruys H, Sotiriadis A, Lakasing L, Spencer K, Nicolaides KH. Coelomic Fluid Leptin Concentration in Normal First-Trimester Pregnancies and Missed Miscarriages. Fetal Diagn Ther 2005; 20:406-9. [PMID: 16113562 DOI: 10.1159/000086821] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2004] [Accepted: 07/13/2004] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Investigation of the possible role of leptin in early pregnancy failure. METHODS Leptin concentration was measured in maternal serum, coelomic fluid and amniotic fluid from 15 singleton pregnancies with live fetuses and 7 missed miscarriages at 7-10 weeks of gestation. RESULTS In the pregnancies with live fetuses, the median leptin concentration was significantly higher in coelomic fluid (median 33.1 ng/ml) than in maternal serum (median 8.1 ng/ml) or amniotic fluid (median 0.5 ng/ml). In the pregnancies with missed miscarriage, compared to those with live fetuses, the median leptin concentration in coelomic fluid was higher (median 45.3 ng/ml), but in maternal serum it was not significantly different (median 5.5 ng/ml). CONCLUSIONS The high coelomic fluid leptin concentration suggests that embryonic death may be preceded by impaired oxygenation of the placenta that stimulates production of leptin.
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Affiliation(s)
- G Makrydimas
- Department of Obstetrics and Gynaecology, Ioannina University Hospital, Ioannina, Greece.
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32
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Cervero A, Horcajadas JA, Domínguez F, Pellicer A, Simón C. Leptin system in embryo development and implantation: a protein in search of a function. Reprod Biomed Online 2005; 10:217-23. [PMID: 15823226 DOI: 10.1016/s1472-6483(10)60943-1] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Implantation is a crucial moment in the reproduction process that requires perfect synchronization between the embryo and the maternal endometrium. The embryo must reach the blastocyst stage and the endometrium must be prepared to receive it. An appropriate and specific molecular dialogue must also take place between them. There is ample evidence to show that the leptin system is implicated in this cross-talk. Examples are described. Although there is some controversy surrounding the data, they are supported by the presence of leptin receptor mRNA in mouse and human oocytes and embryos throughout preimplantation development. Otherwise, the leptin mRNA is only detected at the blastocyst stage in both human and mouse. Furthermore, leptin is found at higher concentrations in the conditioned media from competent human blastocysts than in those from arrested embryos, suggesting that this molecule is a marker for blastocyst viability. Given that expression of the leptin receptor increases in the human endometrium during the luteal phase, the secreted leptin could trigger its activation. Finally, leptin and the leptin receptor have been detected in implantation sites. All these findings point to the involvement of the leptin system in the molecular mechanism of the implantation process and embryo development.
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33
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Malik NM, Carter ND, Wilson CA, Scaramuzzi RJ, Stock MJ, Murray JF. Leptin expression in the fetus and placenta during mouse pregnancy. Placenta 2005; 26:47-52. [PMID: 15664410 DOI: 10.1016/j.placenta.2004.03.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/31/2004] [Indexed: 11/22/2022]
Abstract
During pregnancy, leptin concentrations in the maternal circulation are elevated in both humans and rodents but decrease to pre-pregnancy levels at birth, suggesting a role for leptin in the maintenance of pregnancy. Synthesis of leptin by the human placenta is established but whether the murine placenta synthesizes leptin remains controversial. The aims of this study were to determine (a) if the mouse wild-type placenta expresses the ob gene using Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and (b) whether the mouse fetus and placenta contribute to the significant increase of leptin in the maternal circulation during pregnancy. The mouse placenta did not express the ob gene at a level that could be readily detected using RT-PCR. Moreover, both maternal gain in weight and undetectable concentrations of leptin in sera in leptin-deficient ob/ob mothers bearing heterozygote (ob/+) fetuses suggested that the mouse fetus and placenta do not make a significant contribution to the dramatic increase in maternal plasma concentrations of leptin during late gestation. It is therefore concluded that neither fetal- nor placental-derived leptin modulates maternal weight gain during pregnancy.
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Affiliation(s)
- N M Malik
- Department of Basic Medical Sciences, St Georges Hospital Medical School, London SW17 0RE, UK.
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Abstract
The hormone leptin is produced by adipose tissue and can function as a signal of nutritional status to the reproductive system. The expression of leptin receptor and, in some species, leptin, in the placenta suggests a role for leptin in placental development, but this role has not been elucidated. Leptin is required at the time of embryo implantation in the leptin-deficient ob/ ob mouse and has been shown to upregulate expression of matrix metalloproteinases (MMPs), enzymes involved in trophoblast invasion, in cultured human trophoblast cells. This led us to the hypothesis that leptin promotes the invasiveness of trophoblast cells crucial to placental development. We found that leptin stimulated mouse trophoblast cell invasion through a matrigel-coated insert on Day 10, but not Day 18 of pregnancy. Optimal stimulation occurred at a concentration of 50 ng/ml leptin, similar to the peak plasma leptin concentration during pregnancy in the mouse. Leptin treatment did not stimulate proliferation of mouse trophoblast cells in primary culture. Leptin stimulation of invasion was prevented by 25 muM GM6001, an inhibitor of MMP activity. Our results suggest that leptin may play a role in the establishment of the placenta during early pregnancy and that this function is dependent on MMP activity. This effect of leptin may represent one mechanism by which body condition affects placental development.
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Affiliation(s)
- Laura C Schulz
- Department of Biology, Boston University, Boston, Massachusetts 02215, USA.
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Ladyman SR, Grattan DR. Region-specific reduction in leptin-induced phosphorylation of signal transducer and activator of transcription-3 (STAT3) in the rat hypothalamus is associated with leptin resistance during pregnancy. Endocrinology 2004; 145:3704-11. [PMID: 15142988 DOI: 10.1210/en.2004-0338] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Leptin concentrations increase during pregnancy, but this does not prevent the pregnancy-induced increase in food intake, suggesting a state of leptin resistance. This study investigated the response to intracerebroventricular leptin administration in pregnant rats. After fasting, nonpregnant, d-7 and d-14 pregnant rats received leptin (4 microg) or vehicle, then food intake was measured. Serial blood samples were collected in another group of rats to determine plasma leptin concentrations. Further groups of d-14 pregnant and nonpregnant rats were killed after leptin or vehicle treatment, and brains were collected. Hypothalamic nuclei were microdissected, and levels of signal transducer and activator of transcription (STAT)3 phosphorylation were measured using Western blot analysis. Fasting decreased leptin concentrations in both pregnant and nonpregnant rats. Leptin treatment significantly reduced food intake in nonpregnant and d-7 pregnant rats but not in d-14 pregnant rats. In addition, there was no postfasting hyperphagic response in the pregnant rats. In the pregnant rats, leptin-induced STAT3 phosphorylation was suppressed in the arcuate nucleus and, to a lesser extent, in the ventromedial hypothalamus (VMH), compared with nonpregnant rats. Unstimulated STAT3 levels were also decreased in the VMH during pregnancy. Leptin-induced phosphorylation of STAT3 in the dorsomedial and lateral hypothalamus was not different between pregnant and nonpregnant rats. These data indicate that pregnant rats become resistant to the satiety action of leptin. Furthermore, leptin-induced activation of the STAT3 is impaired during pregnancy, specifically in the arcuate nucleus and VMH. These data support the hypothesis that pregnancy is a state of hypothalamic leptin resistance.
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Affiliation(s)
- S R Ladyman
- Department of Anatomy and Structural Biology, University of Otago, Dunedin 9001, New Zealand
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36
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Veselský L, Holán V, Dostál J, Zelezná B. Boar seminal immunosuppressive fraction attenuates the leptin concentration and restores the thymus mass during pregnancy in mice. Reproduction 2004; 127:581-5. [PMID: 15129013 DOI: 10.1530/rep.1.00008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The immunosuppressive fraction (ISF) of boar seminal vesicle fluid was recently demonstrated to inhibit production of T helper (Th)1 cytokines and enhance production of Th2 cytokines. The present study shows the effect of the ISF on leptin concentrations in blood plasma and adipose tissue in mice during pregnancy. The ISF effect on thymus weight during pregnancy is also demonstrated. The leptin concentration in blood plasma and adipose tissue increased and remained high in the latter half of pregnancy. ISF treatment at the beginning of pregnancy significantly lowered the leptin concentration both in blood plasma and adipose tissue of pregnant mice. Thymus involution has been described previously in pregnant mice. ISF treatment compensated for the loss of thymus mass during the whole pregnancy in the ISF-treated mice. The treatment of pregnant mice with ISF did not affect pregnancy and litter size.
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Affiliation(s)
- L Veselský
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, 166 37 Prague 6, Czech Republic.
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Stocker C, O'Dowd J, Morton NM, Wargent E, Sennitt MV, Hislop D, Glund S, Seckl JR, Arch JRS, Cawthorne MA. Modulation of susceptibility to weight gain and insulin resistance in low birthweight rats by treatment of their mothers with leptin during pregnancy and lactation. Int J Obes (Lond) 2003; 28:129-36. [PMID: 14557827 DOI: 10.1038/sj.ijo.0802476] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVES To investigate whether administration of leptin to rats during pregnancy and lactation affects placental 11beta-hydroxysteroid dehydrogenase (11beta-HSD2) activity and the susceptibility of their offspring to weight gain and insulin resistance. DESIGN Pregnant rats fed on a low-protein diet were administered leptin or saline by subcutaneous minipump from day 14 of gestation and throughout lactation. A further group was fed a normal diet and given saline. After weaning, the offspring of each group were fed on a normal diet until 6 weeks of age and then half of each group was transferred to a high-fat diet until 12 months of age. RESULTS Plasma leptin levels were raised two-fold on days 16-18 of pregnancy in the leptin-treated dams, but, despite a constant rate of infusion, at parturition they dipped to control levels before rising again. The activity of placental 11beta-HSD2 was reduced by the low-protein diet; this reduction was prevented by treating the dams with leptin. The male offspring of the saline-treated dams gained more weight and had higher plasma leptin levels on the high fat than the chow diet, but the offspring of the leptin-treated dams did not. Fasting blood glucose and intraperitoneal glucose tolerance at 6 and 12 months of age was unaffected by the high-fat diet, but only the offspring of the leptin-treated dams achieved this control without raised insulin levels. CONCLUSIONS The rate of leptin clearance appears to increase at parturition. The administration of leptin to rats during late pregnancy and lactation makes their male offspring less susceptible to high-fat-diet-induced weight gain and insulin resistance.
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Affiliation(s)
- C Stocker
- Clore Laboratory, University of Buckingham, Buckingham, UK
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Zhao J, Kunz TH, Tumba N, Schulz LC, Li C, Reeves M, Widmaier EP. Comparative analysis of expression and secretion of placental leptin in mammals. Am J Physiol Regul Integr Comp Physiol 2003; 285:R438-46. [PMID: 12702488 DOI: 10.1152/ajpregu.00776.2002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Increased plasma level of leptin appears to be a ubiquitous feature of pregnant mammals. The mechanisms by which leptin levels are increased may be species specific, however, with some species upregulating adipose leptin production and others expressing leptin in the placenta. Placental leptin expression was examined in representative species of the two most abundant mammalian orders, Rodentia and Chiroptera, and in cultured human choriocarcinoma (BeWo) cells. Leptin mRNA was expressed in BeWo cells and in placentas of Myotis lucifugus (little brown bat), Eptesicus fuscus (big brown bat), and Rattus norvegicus (laboratory rat), but not the common laboratory mouse Mus musculus. cAMP stimulated secretion of leptin from BeWo cells and also stimulated leptin mRNA expression in the cells. In addition to adipose and placental tissue, leptin transcript in M. lucifugus was detectable in heart, spleen, and liver, but not in lung, brain, and kidney. Hepatic expression was also observed in E. fuscus, but not in mice or rats, and did not appear to result from hepatic fat deposition. Leptin cDNA was cloned and sequenced from M. lucifugus placenta and shared up to 95% homology with other mammalian leptin cDNAs. It is concluded that 1) placental leptin expression and secretion are species-specific traits, 2) placental leptin production represents one of three major mechanisms for achieving high circulating maternal leptin levels during pregnancy, the others being upregulation of adipose leptin production and production of circulating leptin-binding proteins, and 3) hepatic leptin expression in pregnant insectivorous bats may be an adaptation resulting from the presence of extremely low amounts of subcutaneous fat during pregnancy and lactation in these species.
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Affiliation(s)
- Jing Zhao
- Department of Biology, Boston University, Boston, MA 02215, USA
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39
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Secretion and regulatory mechanism of leptin during pregnancy in the golden hamster (Mesocricetus auratus). CHINESE SCIENCE BULLETIN-CHINESE 2003. [DOI: 10.1007/bf03185765] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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40
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Soliman M, Ishioka K, Yoshida R, Komabayashi K, Hatai H, Matsui Y, Hirai T, Katagiri S, Takahashi Y, Kawakita Y, Abe H, Kitamura H, Kimura K, Saito M. Serum leptin levels during the periparturient period in cows. J Vet Med Sci 2002; 64:1053-6. [PMID: 12499694 DOI: 10.1292/jvms.64.1053] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Serum leptin concentrations were measured in antenatal and postnatal cows housed at two different locations. The mean serum leptin concentration was 9.2 +/- 0.6 ng/m l (n=22) in one group, and was slightly lower in the other (7.4 +/- 0.4 ng/ml, n=54), probably because of the different nutritional conditions between the two groups. There was no consistent variation in relation to the menstrual cycle and the periparturient period in both groups. Moreover, serum leptin concentrations during the periparturient period were independent of the number of delivery and the incidence of mastitis and milk fever. These results are quite different from those in rodents and human, suggesting the different regulatory mechanism of circulating leptin concentration in cows.
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Affiliation(s)
- Mohamed Soliman
- Laboratory of Biochemistry, Department of Biomedical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
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41
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Mistry AM, Romsos DR. Intracerebroventricular leptin administration reduces food intake in pregnant and lactating mice. Exp Biol Med (Maywood) 2002; 227:616-9. [PMID: 12192103 DOI: 10.1177/153537020222700809] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Leptin acts within the hypothalamus to diminish food intake. During pregnancy and lactation, both circulating leptin concentrations and food intake are elevated, suggesting an ineffectiveness of leptin to reduce food intake in these mice. Thus, this study tested the ability of intracerebroventricular (ICV) leptin administration to alter food intake during pregnancy and lactation. Mice during the first, second, and third trimesters of pregnancy, lactating mice on postpartum Day 7, and age-matched female mice were used. Plasma leptin concentrations averaged 2.9 +/- 0.3 ng/ml in control mice, increased steadily as pregnancy progressed (3.4 +/- 0.7, 29.8 +/- 4.5, and 40.5 +/- 0.7 ng/ml during the first, second, and third trimesters, respectively), and remained elevated on Day 7 postpartum (26.4 +/- 7.8 ng/ml). Mice were food deprived for 4 h, injected ICV with vehicle or leptin (1 micro g), and food intake was subsequently measured hourly for 3 hr, and after 24 hr. Vehicle-treated pregnant mice consumed marginally more food than cycling control mice, whereas nursing dams ate two to three times as much food as controls. As expected, ICV leptin administration reduced 24-hr food intake of control mice by 2 g, or approximately 50%. ICV-administered leptin was as effective in reducing food intake of pregnant and lactating mice as observed in control mice. Thus, the elevated circulating leptin concentrations observed in pregnant and nursing mice did not alter the ability of ICV-administered leptin to diminish food intake. High plasma concentrations of leptin-binding proteins observed during pregnancy, and probably during lactation, may limit the amount of endogenous leptin reaching the hypothalamus, and may consequently enable increases in food intake concomitant with elevated plasma leptin during these nutritionally demanding periods.
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Affiliation(s)
- Anahita M Mistry
- Department of Food, Nutrition, and Exercise Sciences, Florida State University, Tallahassee, Florida 32306-1493, USA
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Yuen BSJ, Owens PC, McFarlane JR, Symonds ME, Edwards LJ, Kauter KG, McMillen IC. Circulating leptin concentrations are positively related to leptin messenger RNA expression in the adipose tissue of fetal sheep in the pregnant ewe fed at or below maintenance energy requirements during late gestation. Biol Reprod 2002; 67:911-6. [PMID: 12193402 DOI: 10.1095/biolreprod.101.002931] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
We have investigated the effects of maternal undernutrition during late gestation on maternal and fetal plasma concentrations of leptin and on leptin gene expression in fetal perirenal adipose tissue. Pregnant ewes were randomly assigned at 115 days of gestation (term = 147 +/- 3 days [mean +/- SEM]) to either a control group (n = 13) or an undernourished group (n = 16) that received approximately 50% of the control diet until 144-147 days of gestation. Maternal plasma glucose, but not leptin, concentrations were lower in the undernourished ewes. A significant correlation was found, however, between mean maternal plasma leptin (y) and glucose (x) concentrations (y = 2.9x - 2.4; r = 0.51, P < 0.02) when the control and undernourished groups were combined. Fetal plasma glucose and insulin, but not fetal leptin, concentrations were lower in the undernourished ewes, and no correlation was found between mean fetal leptin concentrations and either mean fetal glucose or insulin concentrations. A positive relationship, however, was found between mean fetal (y) and maternal (x) plasma leptin concentrations (y = 0.18x + 0.45; r = 0.66, P < 0.003). No significant difference was found in the relative abundance of leptin mRNA in fetal perirenal fat between the undernourished (0.60 +/- 0.09, n = 10) and control (0.70 +/- 0.08, n = 10) groups. Fetal plasma concentrations of leptin (y) and leptin mRNA levels (x) in perirenal adipose tissue were significantly correlated (y = 1.5x +/- 0.3; r = 0.69, P < 0.05). In summary, the capacity of leptin to act as a signal of moderate maternal undernutrition may be limited before birth in the sheep.
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Affiliation(s)
- B S J Yuen
- Department of Physiology, Adelaide University, South Australia 5005, Australia
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Seeber RM, Smith JT, Waddell BJ. Plasma leptin-binding activity and hypothalamic leptin receptor expression during pregnancy and lactation in the rat. Biol Reprod 2002; 66:1762-7. [PMID: 12021059 DOI: 10.1095/biolreprod66.6.1762] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Leptin, the 16-kDa peptide hormone product of the ob gene, regulates body weight via the hypothalamus but also influences several aspects of reproductive function. Results of previous studies have suggested that pregnancy is a state of leptin resistance, because food consumption remains stable or increases despite a progressive rise in plasma leptin across most of gestation. In the present study, we assessed whether this apparent leptin resistance during rat pregnancy was due to either increased plasma leptin-binding activity and/or reduced expression of hypothalamic leptin receptor. Plasma leptin increased from 2.2 +/- 0.4 ng/ml before pregnancy to a maximum at midgestation (4.2 +/- 0.8 ng/ml on Day 12) and then fell by Day 22 and remained low throughout lactation. Despite the higher plasma leptin levels in pregnancy, food consumption increased from a minimum of 13.6 +/- 0.5 g/day before pregnancy to a peak of 21.9 +/- 0.6 g/day on Day 19, then fell before parturition (11.9 +/- 0.4 g/day on Day 22). At least part of the increase in plasma leptin during pregnancy was attributable to a marked increase (P < 0.001) in plasma leptin-binding activity between diestrus and late pregnancy, which then fell after birth but remained at midpregnancy levels to at least Day 12 of lactation. Hypothalamic expression of mRNA encoding the long form of the leptin receptor (Ob-Rb) was elevated in early pregnancy (Day 7) but returned to prepregnancy levels by midgestation and remained stable thereafter. The results of this study confirm that pregnancy in the rat is a state of relative leptin resistance, which is due primarily to increased plasma leptin-binding activity rather than to changes in hypothalamic Ob-Rb expression.
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Affiliation(s)
- Ruth M Seeber
- School of Anatomy and Human Biology and The Western Australian Institute for Medical Research, University of Western Australia, Crawley, Perth, Western Australia 6009, Australia
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Bajoria R, Sooranna SR, Ward BS, Chatterjee R. Prospective function of placental leptin at maternal-fetal interface. Placenta 2002; 23:103-15. [PMID: 11945077 DOI: 10.1053/plac.2001.0769] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Leptin is an endocrine and a growth factor which is important for regulation of body fat, feeding, and energy homeostasis. The anti-obesity function of leptin has been recently extended to reproduction, puberty and pregnancy as an endocrine signal to the hypothalamus. Leptin controls the functional integrity of the feto-placental unit thereby maintaining pregnancy by virtue of its immunomodulatory property via T lymphocytes or other proto-oncogenes. Dysregulation of autocrine/paracrine function of leptin at feto-placento-maternal interface may be implicated in the pathogenesis of recurrent miscarriage gestational diabetes, pre-eclampsia and intra-uterine fetal growth retardation including disturbance of fetal bone turnover. This review will focus on the role of leptin in normal and abnormal pregnancy and fetal growth.
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Affiliation(s)
- R Bajoria
- Academic Unit of Obstetrics and Gynaecology, University of Manchester, St Mary's Hospital, Whitworth Park, Manchester M13 0JH, UK.
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45
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Abstract
Since the cloning of leptin by Friedman's laboratory in 1994, over 3000 papers have been published on leptin, making it one of the most active research areas in all of science. Leptin appears to be a pleiotrophic hormone affecting many different tissues in the body. This review focuses on the role of leptin in reproduction. Evidence is accumulating that leptin potentially has roles in the regulation of GnRH and LH secretion, puberty, pregnancy, and lactation. Reciprocal regulation of leptin and its receptors by gonadal hormones and the implications and controversies thereof are also discussed in the review. Signaling pathways utilized by leptin are starting to become more clear, particularly JAK/STAT, MAPK, and SOCS3 have been implicated as mediators/modulators of leptin effects at the cellular level. At the hypothalamic level, there is also evidence that CART (cocaine and amphetamine-related transcript) is involved as a downstream mediator of leptin effects, especially with regards to control of GnRH secretion. While leptin clearly has many effects upon the reproductive axis, defining its precise roles is not without controversies. This review presents both pro and con findings, thereby demarking controversial areas that undoubtedly will be fertile ground for future investigation.
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Affiliation(s)
- Darrell W Brann
- Neurobiology Program, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA 30912, USA.
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Malik NM, Carter ND, Murray JF, Scaramuzzi RJ, Wilson CA, Stock MJ. Leptin requirement for conception, implantation, and gestation in the mouse. Endocrinology 2001; 142:5198-202. [PMID: 11713215 DOI: 10.1210/endo.142.12.8535] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The ob/ob mouse has a complete absence of circulating leptin, resulting in obesity and infertility. Using the minimum daily dose of leptin required to maintain normal body weight and sexual maturation (5 mg/kg, ip), leptin-treated ob/ob females were mated with either wild-type (+/+) or leptin-treated ob/ob males. The leptin treatment continued throughout pregnancy until weaning or was withdrawn at 0.5, 3.5, 6.5, or 14.5 d post coitum (dpc). Normal pregnancy and parturition with pups of normal weight resulted when ob/ob females were mated with +/+ males and leptin treatment was continued throughout pregnancy (6 of 8 pregnancies), to 14.5 dpc (6 of 8 pregnancies), or to 6.5 dpc (9 of 12 pregnancies). Pregnancy did not result when treatment was stopped at 3.5 dpc (1 of 7 pregnancies) or 0.5 dpc (0 of 6 pregnancies). Similar results were obtained when leptin-treated ob/ob females were mated with leptin-treated ob/ob males. The newborn pups failed to survive after birth in groups treated with leptin up to 14.5 and 6.5 dpc despite reinstating leptin at birth. This appeared to be due to a lack of development of the mammary glands. In conclusion, we have shown that leptin is essential for normal preimplantation and/or implantation processes. It is also essential for normal development of the mammary glands, but is not required for pregnancy and parturition once implantation is established.
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Affiliation(s)
- N M Malik
- Department of Physiology, St. Georges Hospital Medical School, London, United Kingdom SW17 0RE.
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Johnstone LE, Higuchi T. Food intake and leptin during pregnancy and lactation. PROGRESS IN BRAIN RESEARCH 2001; 133:215-27. [PMID: 11589132 DOI: 10.1016/s0079-6123(01)33016-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Successful reproduction requires the accumulation of energy reserves. Although acute and chronic food deprivation disrupts reproduction, surprisingly, an over-abundance of energy reserves can also result in infertility. The infertility of obese, ob/ob mice can be reversed by the reintroduction of leptin, the protein product of the ob gene. In rats, energy reserves are increased during pregnancy by far accumulation and during lactation by hyperphagia. We have therefore investigated the interactions of leptin and food intake during late pregnancy and lactation in rats. Cycling rats consume their daily food intake during the dark phase and this is accompanied by a subsequent increase in plasma leptin concentration compared to light levels. During late pregnancy, rats increase their food intake during the dark phase and this is accompanied by a nocturnal increase in plasma leptin level. However, the nocturnal increase is not seen on the day prior to parturition, and is absent throughout lactation. Surprisingly, despite the massive increase in food intake during lactation plasma leptin levels continue to fall, suggesting that leptin release in response to food intake is suppressed during lactation. Furthermore, central leptin administration is less effective in reducing food intake in late pregnant and early lactating rats compared to cycling rats which suggests that these rats are insensitive to leptin. This may result from downregulation of brain leptin receptors. Decreased leptin production and action during late pregnancy and lactation will result in a decreased satiety effect, with up-regulation of orexigenic factors that produce hyperphagia, so allowing adequate energy intake for successful rearing of offspring.
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Affiliation(s)
- L E Johnstone
- Department of Biomedical Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
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Ingvartsen KL, Boisclair YR. Leptin and the regulation of food intake, energy homeostasis and immunity with special focus on periparturient ruminants. Domest Anim Endocrinol 2001; 21:215-50. [PMID: 11872319 DOI: 10.1016/s0739-7240(02)00119-4] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The biology of leptin has been studied most extensively in rodents and in humans. Leptin is involved in the regulation of food intake, energy homeostasis and immunity. Leptin is primarily produced in white adipose tissue and acts via a family of membrane bound receptors, including an isoform with a long intracellular domain (OB-Rb), and many isoforms with short intracellular domains (Ob-Rs). OB-Rb is predominantly expressed in the hypothalamic regions involved in the regulation of food intake and energy homeostasis. The other isoforms are distributed ubiquitously and are found in most peripheral tissues in far greater abundance than OB-Rb. The effects of leptin on food intake and energy homeostasis are central and are mediated via a network of orexigenic neuropeptides (neuropeptide Y, galanin, galanin-like peptide, melanin-concentrating hormone, orexins, agouti-related peptide) and anorexigenic neuropeptides (corticotropin-releasing hormone, pro-opiomelanocortin, alpha-melanocyte stimulating hormone and cocaine- and amphetamine-regulated transcript). In addition, leptin acts directly on immune cells to stimulate hematopoesis, T-cell immunity, phagocytosis, cytokine production, and to attenuate susceptibility to infectious insults. Emerging data in ruminants suggest that leptin is dynamically regulated by many factors and physiological states. Thus, leptin is secreted in a pulsatile fashion, but without a marked diurnal rhythm. A positive relationship between adiposity and plasma leptin concentration exists in growing and lactating ruminants. The concentration of plasma leptin increases during pregnancy, starts to decline 1--2 wk before parturition, and reaches a nadir in early lactation. The reduction of plasma leptin at parturition is likely to promote centrally mediated adaptations required in periods of energy deficit, but could have negative effects on immune cell function. Future research is needed in ruminants to address the roles played by leptin and the central nervous system in orchestrating metabolism during the periparturient period and during infectious diseases.
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Affiliation(s)
- K L Ingvartsen
- Danish Institute of Agricultural Sciences, Department of Animal Health and Welfare, Research Centre Foulum, DK-8830, Tjele, Denmark.
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Abstract
Since its discovery in 1994, leptin, a protein hormone synthesized and secreted by adipose tissue, has been shown to regulate feed intake in several species including sheep and pigs. Although a nimiety of information exists regarding the physiological role of leptin in rodents and humans, the regulation and action of leptin in domestic animals is less certain. Emerging evidence in several species indicates that leptin may also affect the hypothalamo-pituitary-gonadal axis. Leptin receptor mRNA is present in the anterior pituitary and hypothalamus of several species, including sheep. In rats, effects of leptin on GnRH, LH and FSH secretion have been inconsistent, with leptin exhibiting both stimulatory and inhibitory action in vivo and in vitro. Evidence to support direct action of leptin at the level of the gonad indicates that the leptin receptor and its mRNA are present in ovarian tissue of several species, including cattle. These leptin receptors are functional, since leptin inhibits insulin-induced steroidogenesis of both granulosa and thecal cells of cattle in vitro. Leptin receptor mRNA is also found in the testes of rodents. As with the ovary, these receptors are functional, at least in rats, since leptin inhibits hCG-induced testosterone secretion by Leydig cells in vitro. During pregnancy, placental production of leptin may be a major contributor to the increase in maternal leptin in primates but not rodents. However, in both primates and rodents, leptin receptors exist in placental tissues and may regulate metabolism of the fetal-placental unit. As specific leptin immunoassays are developed for domestic animals, in vivo associations may then be made among leptin, body energy stores, dietary energy intake and reproductive function. This may lead to a more definitive role of leptin in domestic animal reproduction.
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Affiliation(s)
- L J Spicer
- Department of Animal Science, Oklahoma State University, Stillwater, Oklahoma 74078, USA.
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50
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Abstract
Maternal plasma leptin is elevated during pregnancy in several species, but it is unclear to what extent this elevation reflects changes in adiposity or energy balance. Therefore, Karakul ewes (n = 8) were fed to minimize changes in maternal energy status over the pregnancy-lactation cycle. They were studied 20-40 d before breeding and during mid pregnancy (d 50-60 post coitus [PC]), late pregnancy (d 125-135 PC) and early lactation (d 15-22 post partum). Consistent with the maintenance of near energy equilibrium in nongravid maternal tissues, maternal body weight was increased only during late pregnancy when the weight of the conceptus became significant and plasma concentrations of insulin, NEFA and glucose did not vary with physiological state. In contrast, maternal plasma leptin concentration rose from 5.3 to 9.5 ng/mL between prebreeding and mid pregnancy and then declined progressively through late pregnancy and early lactation. Leptin gene expression increased 2.3 fold in maternal white adipose tissue (WAT) from prebreeding to mid pregnancy and declined to prebreeding levels during early lactation. To determine whether tissue response to insulin was involved in this effect, insulin tolerance tests were performed. The maternal plasma glucose response declined from prebreeding to early lactation, but was not correlated with either plasma leptin concentration or WAT leptin mRNA abundance. In conclusion, pregnancy causes an increase in the synthesis of leptin in sheep. This stimulation does not require increases in adiposity or energy balance and is unrelated to the ability of insulin to promote glucose utilization.
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Affiliation(s)
- R A Ehrhardt
- Department of Animal Science, Cornell University, Ithaca, NY 14853, USA
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