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Haddad-Tóvolli R, Claret M. Metabolic and feeding adjustments during pregnancy. Nat Rev Endocrinol 2023; 19:564-580. [PMID: 37525006 DOI: 10.1038/s41574-023-00871-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/29/2023] [Indexed: 08/02/2023]
Abstract
Eating behaviours are determined by the integration of interoceptive and environmental inputs. During pregnancy, numerous physiological adaptations take place in the maternal organism to provide an adequate environment for embryonic growth. Among them, whole-body physiological remodelling directly influences eating patterns, commonly causing notable taste perception alterations, food aversions and cravings. Recurrent food cravings for and compulsive eating of highly palatable food can contribute to the development and maintenance of gestational overweight and obesity with potential adverse health consequences for the offspring. Although much is known about how maternal eating habits influence offspring health, the mechanisms that underlie changes in taste perception and food preference during pregnancy (which guide and promote feeding) are only just starting to be elucidated. Given the limited and diffuse understanding of the neurobiology of gestational eating patterns, the aim of this Review is to compile, integrate and discuss the research conducted on this topic in both experimental models and humans. This article sheds light on the mechanisms that drive changes in female feeding behaviours during distinct physiological states. Understanding these processes is crucial to improve gestational parent health and decrease the burden of metabolic and food-related diseases in future generations.
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Affiliation(s)
- Roberta Haddad-Tóvolli
- Neuronal Control of Metabolism (NeuCoMe) Laboratory, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.
| | - Marc Claret
- Neuronal Control of Metabolism (NeuCoMe) Laboratory, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Barcelona, Spain.
- School of Medicine, Universitat de Barcelona, Barcelona, Spain.
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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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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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Zhang JY, Zhao XY, Wen J, Tan S, Zhao ZJ. Plasticity in gastrointestinal morphology and enzyme activity in lactating striped hamsters (Cricetulus barabensis). J Exp Biol 2016; 219:1327-36. [DOI: 10.1242/jeb.138396] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 02/19/2016] [Indexed: 11/20/2022]
Abstract
In small mammals marked phenotypic plasticity of digestive physiology has been shown to make it easier to cope with the energetically stressful periods, such as lactation. It has been proposed that the capacity of the gut to digest and absorb food is not the factor limiting to sustained energy intake (SusEI) during peak lactation. In this study, plasticity in energy intake and gastrointestinal morphology was examined in striped hamsters at different stages of reproduction and raising litters of different sizes. Mechanisms associated with digestive enzymes and neuroendocrine hormones underpinning the plasticity were also examined. The females significantly increased energy intake, digestibility, masses of digestive tracts and activity of stomach pepsin and maltase, sucrase and aminopeptidase of small intestine in peak lactation compared to the non-productive and post-lactating periods. Further, the females raising large litters significantly increased energy intake, digestibility, gastrointestinal mass and activity of digestive enzymes, and weaned heavier offspring compared with those nursing small and medium litters, indicating that the significant plasticity of digestive physiology increased reproductive performance. The agouti-related protein (AgRP) mRNA expression in the hypothalamus was up-regulated significantly in the females raising large litters relative to those raising small litters. Serum leptin levels, hypothalamus neuropeptide Y (NPY), or anorexigenic neuropeptides (pro-opiomelanocortin / cocaine- and amphetamine-regulated transcript, POMC / CART) mRNA expression did not differ among the females raising small, medium and large litters, indicating that leptin levels in lactation might only reflect a state of energy balance rather than being the prime driver of hyperphagia. Some hypothalamic neuropeptides, such as NPY, POMC and CART, would be involved in the limits to the SusEI during lactation.
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Affiliation(s)
- Ji-Ying Zhang
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Xiao-Ya Zhao
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Jing Wen
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Song Tan
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Zhi-Jun Zhao
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
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Abstract
Leptin, as a key hormone in energy homeostasis, regulates neuroendocrine function, including reproduction. It has a permissive role in the initiation of puberty and maintenance of the hypothalamic-pituitary-gonadal axis. This is notable in patients with either congenital or acquired leptin deficiency from a state of chronic energy insufficiency. Hypothalamic amenorrhea is the best-studied, with clinical trials confirming a causative role of leptin in hypogonadotropic hypogonadism. Implications of leptin deficiency have also emerged in the pathophysiology of hypogonadism in type 1 diabetes. At the other end of the spectrum, hyperleptinemia may play a role in hypogonadism associated with obesity, polycystic ovarian syndrome, and type 2 diabetes. In these conditions of energy excess, mechanisms of reproductive dysfunction include central leptin resistance as well as direct effects at the gonadal level. Thus, reproductive dysfunction due to energy imbalance at both ends can be linked to leptin.
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Affiliation(s)
- Sharon H Chou
- Section of Adult and Pediatric EndocrinologyDiabetes and Metabolism, The University of Chicago, 5841 South Maryland Avenue, MC 1027, Chicago, Illinois 60637, USADivision of EndocrinologyDiabetes, and Metabolism, Harvard Medical School, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, FD-876, Boston, Massachusetts 02215, USASection of EndocrinologyBoston VA Healthcare System, Harvard Medical School, Boston, Massachusetts, USA
| | - Christos Mantzoros
- Section of Adult and Pediatric EndocrinologyDiabetes and Metabolism, The University of Chicago, 5841 South Maryland Avenue, MC 1027, Chicago, Illinois 60637, USADivision of EndocrinologyDiabetes, and Metabolism, Harvard Medical School, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, FD-876, Boston, Massachusetts 02215, USASection of EndocrinologyBoston VA Healthcare System, Harvard Medical School, Boston, Massachusetts, USA Section of Adult and Pediatric EndocrinologyDiabetes and Metabolism, The University of Chicago, 5841 South Maryland Avenue, MC 1027, Chicago, Illinois 60637, USADivision of EndocrinologyDiabetes, and Metabolism, Harvard Medical School, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, FD-876, Boston, Massachusetts 02215, USASection of EndocrinologyBoston VA Healthcare System, Harvard Medical School, Boston, Massachusetts, USA
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Pazos P, Lima L, Casanueva FF, Diéguez C, García MC. Interleukin 6 deficiency modulates the hypothalamic expression of energy balance regulating peptides during pregnancy in mice. PLoS One 2013; 8:e72339. [PMID: 24015235 PMCID: PMC3756067 DOI: 10.1371/journal.pone.0072339] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2013] [Accepted: 07/08/2013] [Indexed: 01/03/2023] Open
Abstract
Pregnancy is associated with hyperphagia, increased adiposity and multiple neuroendocrine adaptations. Maternal adipose tissue secretes rising amounts of interleukin 6 (IL6), which acts peripherally modulating metabolic function and centrally increasing energy expenditure and reducing body fat. To explore the role of IL6 in the central mechanisms governing dam's energy homeostasis, early, mid and late pregnant (gestational days 7, 13 and 18) wild-type (WT) and Il6 knockout mice (Il6-KO) were compared with virgin controls at diestrus. Food intake, body weight and composition as well as indirect calorimetry measurements were performed in vivo. Anabolic and orexigenic peptides: neuropeptide Y (Npy) and agouti-related peptide (Agrp); and catabolic and anorectic neuropeptides: proopiomelanocortin (Pomc), corticotrophin and thyrotropin-releasing hormone (Crh and Trh) mRNA levels were determined by in situ hybridization. Real time-PCR and western-blot were used for additional tissue gene expression and protein studies. Non-pregnant Il6-KO mice were leaner than WT mice due to a decrease in fat but not in lean body mass. Pregnant Il6-KO mice had higher fat accretion despite similar body weight gain than WT controls. A decreased fat utilization in absence of Il6 might explain this effect, as shown by increased respiratory exchange ratio (RER) in virgin Il6-KO mice. Il6 mRNA levels were markedly enhanced in adipose tissue but reduced in hypothalamus of mid and late pregnant WT mice. Trh expression was also stimulated at gestational day 13 and lack of Il6 blunted this effect. Conversely, in late pregnant mice lessened hypothalamic Il6 receptor alpha (Il6ra), Pomc and Crh mRNA were observed. Il6 deficiency during this stage up-regulated Npy and Agrp expression, while restoring Pomc mRNA levels to virgin values. Together these results demonstrate that IL6/IL6Ra system modulates Npy/Agrp, Pomc and Trh expression during mouse pregnancy, supporting a role of IL6 in the central regulation of body fat in this physiological state.
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Affiliation(s)
- Patricia Pazos
- Department of Physiology/Research Center of Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela, Santiago de Compostela, Spain
- Instituto de Investigación Sanitaria de Santiago de Compostela, Santiago de Compostela, Spain
- CIBER Fisiopatología Obesidad y Nutrición (CB06/03), Instituto de Salud Carlos III (ISCIII), Ministerio de Economía y Competitividad (MINECO), Santiago de Compostela, Spain
| | - Luis Lima
- Department of Physiology/Research Center of Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela, Santiago de Compostela, Spain
- Instituto de Investigación Sanitaria de Santiago de Compostela, Santiago de Compostela, Spain
| | - Felipe F. Casanueva
- Department of Physiology/Research Center of Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela, Santiago de Compostela, Spain
- Instituto de Investigación Sanitaria de Santiago de Compostela, Santiago de Compostela, Spain
- CIBER Fisiopatología Obesidad y Nutrición (CB06/03), Instituto de Salud Carlos III (ISCIII), Ministerio de Economía y Competitividad (MINECO), Santiago de Compostela, Spain
- Laboratorio de Endocrinología Molecular y Celular, Complexo Hospitalario Universitario de Santiago (CHUS), Santiago de Compostela, Spain
| | - Carlos Diéguez
- Department of Physiology/Research Center of Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela, Santiago de Compostela, Spain
- Instituto de Investigación Sanitaria de Santiago de Compostela, Santiago de Compostela, Spain
- CIBER Fisiopatología Obesidad y Nutrición (CB06/03), Instituto de Salud Carlos III (ISCIII), Ministerio de Economía y Competitividad (MINECO), Santiago de Compostela, Spain
| | - María C. García
- Department of Physiology/Research Center of Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela, Santiago de Compostela, Spain
- Instituto de Investigación Sanitaria de Santiago de Compostela, Santiago de Compostela, Spain
- CIBER Fisiopatología Obesidad y Nutrición (CB06/03), Instituto de Salud Carlos III (ISCIII), Ministerio de Economía y Competitividad (MINECO), Santiago de Compostela, Spain
- * E-mail:
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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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Reichardt F, Krueger D, Schemann M. Leptin excites enteric neurons of guinea-pig submucous and myenteric plexus. Neurogastroenterol Motil 2011; 23:e165-70. [PMID: 21223453 DOI: 10.1111/j.1365-2982.2010.01665.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Leptin, one of the most prominent mediators released from adipocytes, influences neuronal activity in the central nervous system. The enteric nervous system (ENS) expresses leptin receptors but consequence of activation of these receptors on enteric neuron activity has not been systematically studied. An adipocyte-ENS axis is suggested by close apposition between enteric nerves and adipocytes. The aim of this study was to investigate the effects of leptin on guinea-pig submucous and myenteric neurons. METHODS Using voltage sensitive dye imaging, we recorded neural responses to application of leptin (0.0625 nmol L(-1)) in myenteric and submucous neurons, nicotine (10 μmol L(-1)) served as a reference for neuronal excitation. Mucosal ion secretion and muscle activity were measured in vitro with Ussing and organ bath techniques, respectively. KEY RESULTS Leptin induced spike discharge in 13.6% of submucous neurons and in 8.2% of myenteric neurons (1.1 ± 0.9 and 1.2 ± 1.0 Hz, respectively). Although there was an overlap of nicotine and leptin responses, 38.5% of submucous and 25% of myenteric neurons activated by leptin did not respond to nicotine. Leptin did not inhibit ongoing spike discharge or fast excitatory postsynaptic potentials. Leptin (0.0625 nmol L(-1)) did not affect mucosal secretion or muscle activity suggesting a subtle modulatory action of leptin at the level of the ENS. CONCLUSIONS & INFERENCES Leptin activates submucous and myenteric neurons indicating relevance for adipocyte-ENS signaling. These results set the basis for further studies to reveal the functional correlate of the neural action of leptin in the ENS.
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Affiliation(s)
- F Reichardt
- Lehrstuhl für Humanbiologie, Technische Universität München, Liesel-Beckmann-Strasse 4, 85350 Freising-Weihenstephan, Germany
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Zhang XY, Wang DH. Different physiological roles of serum leptin in the regulation of energy intake and thermogenesis between pregnancy and lactation in primiparous Brandt's voles (Lasiopodomys brandtii). Comp Biochem Physiol C Toxicol Pharmacol 2008; 148:390-400. [PMID: 18321785 DOI: 10.1016/j.cbpc.2008.01.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Revised: 01/24/2008] [Accepted: 01/24/2008] [Indexed: 01/26/2023]
Abstract
Reproduction, especially lactation, is associated with major metabolic adaptive changes. In this study, we investigated the metabolic changes and the roles of leptin during different periods of reproduction in primiparous Brandt's voles (Lasiopodomys brandtii). Energy intake, thermogenic capacity and serum leptin levels were examined in non-reproductive, mid pregnant, late pregnant, early lactating and peak lactating voles. Voles increased body mass by nearly 70% during late pregnancy compared to the non-breeding controls. The increase in body mass was mainly due to the increase in body fat mass which increased by 56%, and the growth of the reproductive tissues and digestive organs. Lactating voles decreased body fat by nearly 27% at peak lactation compared to the controls, and 53% compared to late pregnant voles. At the same time they increased food intake significantly. Uncoupling protein 1 (UCP1) content in brown adipose tissue (BAT) decreased significantly at peak lactation. Serum leptin increased significantly in the mid pregnancy, at a time when there was no increase in body fat, and remained at this high level in late pregnancy. Leptin levels decreased after parturition and reached a nadir at peak lactation. Serum leptin was negatively correlated with energy intake during lactation, but not during pregnancy. These data suggest that Brandt's voles adjust energy intake, thermogenic capacity and body reserves to match the high energy demands for reproduction. Hyperleptinemia, without decreased energy intake suggests a state of leptin resistance during pregnancy, and hypoleptinemia during lactation might act as a signal to stimulate energy intake.
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Affiliation(s)
- Xue-Ying Zhang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Datun Lu, Chaoyang, Beijing 100101, China
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Tang GB, Cui JG, Wang DH. Hypothalamic suppressor-of-cytokine-signalling 3 mRNA is elevated and pro-opiomelanocortin mRNA is reduced during pregnancy in Brandt's voles (Lasiopodomys brandtii ). J Neuroendocrinol 2008; 20:1038-44. [PMID: 18638026 DOI: 10.1111/j.1365-2826.2008.01764.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Leptin acts within the hypothalamus to diminish food intake. In Brandt's voles (Lasiopodomys brandtii), both circulating leptin levels and food intake are elevated during pregnancy, suggesting an ineffectiveness of leptin to reduce food intake. Diminished hypothalamic leptin receptors and impaired leptin signal transduction are characteristic of central leptin resistance. The present study aimed to determine whether these characteristic modulations of leptin sensitivity occurred in pregnant Brandt's voles. The mRNA expression of the long form of the leptin receptor (Ob-Rb), suppressor-of-cytokine-signalling 3 (SOCS3), neuropeptide Y (NPY), agouti-related protein (AgRP), pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) in the hypothalamus were examined on dioestrous, day 5, day 10 and day 18 of pregnancy. Compared to controls, there was no significant change in hypothalamic Ob-Rb mRNA during the pregnancy. SOCS3 mRNA was increased significantly by 68% on day 10% and 93% on day 18 of pregnancy compared to controls. Despite elevated leptin levels, POMC mRNA was decreased significantly by 60% on day 18 of pregnancy, whereas no differences were found in the mRNA expression of NPY, AgRP and CART in pregnant voles compared to controls. The elevation of SOCS3 mRNA together with disrupted leptin regulation of neuropeptides in the hypothalamus suggests that leptin resistance may develop in pregnant Brandt's voles.
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Affiliation(s)
- G-B Tang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Datun Lu, Chaoyang, Beijing, China
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11
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Zhang XY, Li YL, Wang DH. Large litter size increases maternal energy intake but has no effect on UCP1 content and serum-leptin concentrations in lactating Brandt's voles (Lasiopodomys brandtii). J Comp Physiol B 2008; 178:637-45. [PMID: 18283466 DOI: 10.1007/s00360-008-0255-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2007] [Revised: 01/31/2008] [Accepted: 02/03/2008] [Indexed: 11/25/2022]
Abstract
Lactation is the most energetically demanding period in the female mammal's life. We measured maternal energy intake, uncoupling protein 1 (UCP1) content in brown adipose tissue (BAT), serum-leptin concentration, and litter growth in lactating Brandt's voles (Lasiopodomys brandtii) with different litter sizes. Litter mass was positively related to litter size but there was no difference in pup mass at birth. Maternal gross energy intake at peak lactation was positively correlated with litter size and litter mass. Maternal resting metabolic rate (RMR) was positively correlated with litter mass, but not with litter size. No significant differences were detected in body-fat mass, serum-leptin concentration, or UCP1 in lactating voles with different litter sizes. Serum-leptin concentration was negatively correlated with energy intake during lactation. Our data did not support the hypothesis that there is a trade-off in energy allocation between maternal maintenance and offspring growth in lactating Brandt's voles, but support the idea that if the mothers with ten pups should have less energy available for their maintenance than mothers raising fewer pups. Also, leptin is probably not the only factor that induces the high energy intake in mothers with large litter sizes, although it was involved in the regulation of energy intake during lactation.
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Affiliation(s)
- Xue-Ying Zhang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Datun Lu, Chaoyang, Beijing 100101, People's Republic of China
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12
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Brunton PJ, Russell JA. The expectant brain: adapting for motherhood. Nat Rev Neurosci 2008; 9:11-25. [PMID: 18073776 DOI: 10.1038/nrn2280] [Citation(s) in RCA: 266] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A successful pregnancy requires multiple adaptations of the mother's physiology to optimize fetal growth and development, to protect the fetus from adverse programming, to provide impetus for timely parturition and to ensure that adequate maternal care is provided after parturition. Many of these adaptations are organized by the mother's brain, predominantly through changes in neuroendocrine systems, and these changes are primarily driven by the hormones of pregnancy. By contrast, adaptations in the mother's brain during lactation are maintained by external stimuli from the young. The changes in pregnancy are not necessarily innocuous: they may predispose the mother to post-partum mood disorders.
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Affiliation(s)
- Paula J Brunton
- Laboratory of Neuroendocrinology, Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, Scotland, UK
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13
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Abstract
Despite elevated plasma leptin, food intake is increased during pregnancy leading to fat deposition. We have demonstrated that intracerebroventricular (icv) leptin is unable to suppress food intake in pregnant rats, as it does in non-pregnant animals. Hence, central leptin resistance develops during pregnancy. These changes are physiologically appropriate, providing increased energy reserves to help meet the high metabolic demands of fetal development and lactation. To characterise this central leptin resistance, we have measured levels of leptin receptor (Ob-Rb) mRNA in the hypothalamus, and examined leptin-induced phosphorylation of STAT3 (pSTAT3) in specific regions of the hypothalamus. In addition, to investigate the mechanism underlying pregnancy-induced leptin resistance, we have investigated effects of hormone treatments on hypothalamic responses to leptin in a pseudopregnant rat model. We observed a significant reduction of Ob-Rb mRNA levels in the ventromedial hypothalamic nucleus (VMH) during pregnancy, with no changes detected in other hypothalamic nuclei. Levels of leptin-induced pSTAT3 were specifically suppressed in the VMH and arcuate nucleus of pregnant rats compared to non-pregnant rats. Pseudopregnant rats were hyperphagic but did not become leptin resistant, suggesting that fetal or placental factors are required for the induction of leptin resistance. These data implicate the VMH as a key hypothalamic site involved in hormone-induced leptin resistance during pregnancy, and suggest that placental hormone secretion may mediate the hormone-induced loss of response to leptin.
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Affiliation(s)
- David R Grattan
- Centre for Neuroendocrinology and Department of Anatomy and Structural Biology, University of Otago, Dunedin, New Zealand.
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14
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Zhang XY, Wang DH. Thermogenesis, food intake and serum leptin in cold-exposed lactating Brandt's volesLasiopodomys brandtii. J Exp Biol 2007; 210:512-21. [PMID: 17234621 DOI: 10.1242/jeb.02659] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYLactation is the most energetically expensive period for mammals and is associated with increased metabolism and energy intake, but decreased thermogenic capacity. It is well known that small mammals increase both food intake and thermogenesis in the cold. The present study aimed to examine whether Brandt's voles Lasiopodomys brandtii could adjust energy intake and thermogenesis to accommodate simultaneous lactation and cold exposure. The voles were placed into two temperature treatments: warm(23±1°C) and cold (5±1°C). Animals at each temperature treatment were further divided into two groups: non-reproductive (NR) and lactating females. We found that lactating voles at peak lactation in the cold enhanced food intake by 2.6 g day–1 compared with those in the warm, and increased uncoupling protein 1 (UCP1) content in brown adipose tissue (BAT), to the same level as the cold-exposed NR females. Serum leptin levels decreased significantly during lactation and were positively correlated with body mass and fat mass. After correcting for the effects of body mass,residual serum leptin was negatively correlated with residual gross energy intake and residual RMR. In addition, residual serum leptin levels were positively correlated with UCP1 contents in the warm, but not in the cold. Together, these data suggest that lactating voles can increase thermogenic capacity and energy intake to meet the high energetic costs of simultaneous lactation and cold exposure. Further, serum leptin appears to be involved in the energy intake regulation and thermoregulation, but the thermoregulation in the cold may be mainly mediated by other factors.
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Affiliation(s)
- Xue-Ying Zhang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 25 Beisihuan Xilu, Zhongguancun, Haidian, Beijing 100080, China
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Abstract
Evidence both from mice and cultured cells suggests an important role of soluble leptin receptors in obesity and leptin signaling. However, the direct effects of soluble receptors on leptin uptake by cells are not clear. This study shows that soluble leptin receptors antagonize the permeation of leptin across the mouse blood-brain barrier by reducing the binding and endocytosis of leptin. This is illustrated by analysis of radioactively labeled and fluorescent-tagged leptin in normal mice and in cultured cells overexpressing various forms of leptin receptors. Three constructs of soluble leptin receptors were generated in this study: ObRe (805 aa), ObR839, and ObR852. (125)I-leptin was injected intravenously and its influx rate from blood to brain determined by multiple-time regression analysis. Pre-incubation with ObR839 caused a significant reduction of leptin influx across the blood-brain barrier. Endocytosis assays and fluorescent image analysis further showed that ObRe, ObR839, and ObR852 failed to mediate leptin internalization and trafficking within the cells. Instead, these soluble receptors inhibited surface binding and endocytosis of leptin. Thus, we provide novel direct evidence both in vivo and in vitro that soluble receptors of leptin serve as antagonists of the transport of leptin.
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Affiliation(s)
- Hong Tu
- Pennington Biomedical Research Center, Baton Rouge, Louisiana 70808, USA
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16
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Speakman JR, Król E. Limits to sustained energy intake IX: a review of hypotheses. J Comp Physiol B 2005; 175:375-94. [PMID: 16047178 DOI: 10.1007/s00360-005-0013-3] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2004] [Revised: 03/08/2005] [Accepted: 05/03/2005] [Indexed: 02/01/2023]
Abstract
Several lines of evidence indicate that animals in the wild may be limited in their maximal rates of energy intake by their intrinsic physiology rather than food availability. Understanding the limits to sustained energy intake is important because this defines an envelope within which animals must trade-off competing activities. In the first part of this review, we consider the initial ideas that propelled this area and experimental evidence connected with them. An early conceptual advance in this field was the idea that energy intake could be centrally limited by aspects of the digestive process, or peripherally limited at the sites of energy utilisation. A model system that has been widely employed to explore these ideas is lactation in small rodents. Initial studies in the late 1980s indicated that energy intake might be centrally limited, but work by Hammond and colleagues in the 1990s suggested that it was more likely that the limits were imposed by capacity of the mammary glands, and other works tended to support this view. This consensus, however, was undermined by studies that showed milk production was higher in mice at low temperatures, suggesting that the capacity of the mammary gland is not a limiting factor. In the second part of the review we consider some additional hypotheses that might explain these conflicting data. These include the heat dissipation limits hypothesis, the seasonal investment hypothesis and the saturated neural control hypothesis. Current evidence with respect to these hypotheses is also reviewed. The limited evidence presently available does not unambiguously support any one of them.
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Affiliation(s)
- John R Speakman
- Aberdeen Centre for Energy Regulation and Obesity, School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, UK.
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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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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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