51
|
Evock-Clover CM, Poch SM, Richards MP, Ashwell CM, McMurtry JP. Expression of an uncoupling protein gene homolog in chickens. Comp Biochem Physiol A Mol Integr Physiol 2002; 133:345-58. [PMID: 12208305 DOI: 10.1016/s1095-6433(02)00113-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
An avian uncoupling protein (UCP) gene homolog was recently sequenced from skeletal muscle and was proposed to have a role in thermogenesis in chickens, ducks and hummingbirds. Since mammalian UCP 2 and UCP 3 also appear to have functions associated with energy and substrate partitioning and body weight regulation, the purpose of this study was to further characterize chicken UCP under conditions of nutritional stress and/or leptin administration. Male 3-week-old chickens were starved for 24 or 48 h and then half of each group was refed for an additional 24 h. In a follow-up experiment, chickens were fed or starved for 48 h with or without leptin administration. Feed deprivation increased UCP mRNA expression in skeletal muscle by up to 260% (P<0.001), and in a time-dependent manner in pectoralis muscle. Refeeding for 24 h normalized muscle UCP mRNA levels. Leptin administration had no effect on muscle UCP. Chicken muscle UCP mRNA levels were highly correlated with plasma triglyceride and non-esterified fatty acid (NEFA) concentrations, and with circulating levels of insulin, insulin-like growth factor (IGF)-I and IGF-II. These results suggest that, as in mammals, avian UCP is up-regulated during feed deprivation and is highly correlated with increased fatty acid oxidation and flux into skeletal muscle.
Collapse
Affiliation(s)
- Christina M Evock-Clover
- Growth Biology Laboratory, US Department of Agriculture - Agricultural Research Service, ANRI, GBL, B-200, R-217, BARC-East, 10300 Baltimore Avenue, Beltsville, MD 20705-2350, USA.
| | | | | | | | | |
Collapse
|
52
|
|
53
|
Taouis M, Dridi S, Cassy S, Benomar Y, Raver N, Rideau N, Picard M, Williams J, Gertler A. Chicken leptin: properties and actions. Domest Anim Endocrinol 2001; 21:319-27. [PMID: 11872323 DOI: 10.1016/s0739-7240(01)00122-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Chicken leptin cDNA shows a high homology to mammalian homologous, with an expression localized in the liver and adipose tissue. It is noteworthy, that the hepatic expression is most likely associated with the primary role that this organ plays in lipogenic activity in avian species. As in mammals, chicken leptin expression is regulated by hormonal and nutritional status. This regulation is tissue-specific and with a high sensitivity in the liver compared to adipose tissue. The blood leptin levels are regulated by the nutritional state with high levels in the fed state compared to the fasted state. The recombinant chicken leptin markedly inhibits food intake as reported in mammals, suggesting the presence of an hypothalamic leptin receptor. The chicken leptin receptor has been identified and all functional motifs are highly conserved compared to mammalian homologous. Chicken leptin receptor is expressed in the hypothalamus but also in other tissues such as pancreas, where leptin inhibits insulin secretion and thus may have a key role in regulating nutrient utilization in this species.
Collapse
Affiliation(s)
- M Taouis
- Station de Recherches Avicoles, Institut National de la Recherche Agronomique, 37380, Nouzilly, France.
| | | | | | | | | | | | | | | | | |
Collapse
|
54
|
Furuse M, Tachibana T, Ohgushi A, Ando R, Yoshimatsu T, Denbow DM. Intracerebroventricular injection of ghrelin and growth hormone releasing factor inhibits food intake in neonatal chicks. Neurosci Lett 2001; 301:123-6. [PMID: 11248438 DOI: 10.1016/s0304-3940(01)01621-4] [Citation(s) in RCA: 126] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Growth hormone releasing factor (GRF) is known to stimulate feeding of rats. Ghrelin, a novel growth hormone (GH)-releasing acylated peptide, was recently isolated from rat stomach. It also stimulates the release of GH from the anterior pituitary through the GH secretagogue receptor (GHS-R) and feeding in the rat. We have investigated the effects of ghrelin and GRF on food intake of the neonatal chick. In Experiment 1, 0, 1.25, 2.5 and 5 microg of ghrelin were administered intracerebroventricularly (i.c.v.) to ad libitum fed birds. In Experiment 2, the effect of (i.c.v.) injection of 0, 1.25, 2.5 and 5 microg of GRF was investigated. Both peptides strongly inhibited food intake of the chick during the 2-h post-injection period. In the third experiment, 0, 0.5, 1 and 2 microg of ghrelin was injected i.c.v. in chicks previously deprived of food for 3 h. Food intake was again inhibited by ghrelin in a dose-dependent manner. These results suggest that the mechanisms for feeding of the neonatal chick through GH release are different from mammals.
Collapse
Affiliation(s)
- M Furuse
- Laboratory of Advanced Animal and Marine Bioresources, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 812-8581, Fukuoka, Japan.
| | | | | | | | | | | |
Collapse
|
55
|
Central Administration of BIBP3226, Neuropeptide Y (NPY) Y1 Receptor Antagonist, does not Inhibit Fasting- and NPY-Induced Food Intake in Neonatal Chicks. J Poult Sci 2001. [DOI: 10.2141/jpsa.38.259] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
|
56
|
Dridi S, Raver N, Gussakovsky EE, Derouet M, Picard M, Gertler A, Taouis M. Biological activities of recombinant chicken leptin C4S analog compared with unmodified leptins. Am J Physiol Endocrinol Metab 2000; 279:E116-23. [PMID: 10893330 DOI: 10.1152/ajpendo.2000.279.1.e116] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The chicken leptin sequence, in contrast to mammalian leptins, contains an unpaired Cys at position 3 of the original cDNA (AF012727). The presence of an extra Cys may confer a different structure and affect the leptin's biological activity. To address this, we studied the effects of wild-type and mutated (C4S) chicken leptins in vitro and in vivo and compared them with mammalian leptin prepared from ovine leptin cDNA. The prokaryotic expression vector pMON, encoding full-size A(-1) chicken leptin (AF012727), was mutated using a mutagenesis kit, yielding the C4S analog. Escherichia coli cells transformed with this vector overexpressed large amounts of chicken leptin C4S upon induction with nalidixic acid. The expressed protein, found in the inclusion bodies, was refolded and purified to homogeneity on a Q-Sepharose column, yielding three electrophoretically pure fractions, eluted from the column by 100, 125, and 150 mM NaCl, respectively. All three fractions showed a single band of the expected molecular mass (16 kDa) and were composed of >95% monomeric protein. Proper refolding was evidenced by comparing the circular dichroism spectrum of the analog with spectra of nonmutated chicken and ovine leptins. The biological activity of the C4S analog was evidenced by its ability to stimulate proliferation of leptin-sensitive BAF/3 cells transfected with a long form of human leptin receptor construct similar to its nonmutated counterpart, indicating that Cys4 plays no role in leptin activity. The in vitro activity of both wild-type and mutated chicken leptins was approximately 10-fold lower than that of ovine leptin. After intravenous or intraperitoneal injections, C4S analog and the nonmutated chicken and ovine leptins all lowered the food intake of starved 9-day-old broiler or 5-wk-old layer male chickens by 11-34%. Monitoring food behavior revealed that the attenuated food intake resulted not from a decreased number of approaches to the feeders but from a decrease in the average time spent eating during each approach.
Collapse
Affiliation(s)
- S Dridi
- Station de Recherches Avicoles, Institut National de la Recherche Agronomique, 37380 Nouzilly, France
| | | | | | | | | | | | | |
Collapse
|
57
|
Kawakami S, Bungo T, Ando R, Ohgushi A, Shimojo M, Masuda Y, Furuse M. Central administration of alpha-melanocyte stimulating hormone inhibits fasting- and neuropeptide Y-induced feeding in neonatal chicks. Eur J Pharmacol 2000; 398:361-4. [PMID: 10862825 DOI: 10.1016/s0014-2999(00)00344-7] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the present study, the effect of intracerebroventricular (i.c.v.) administration of alpha-melanocyte stimulating hormone (alpha-MSH) on food intake of neonatal chicks was examined. In experiment 1, i.c. v. injection of alpha-MSH (0.04, 0.2 and 1 microg) significantly inhibited food intake of 3-h fasted chicks in a dose-dependent manner. In experiment 2, alpha-MSH strongly inhibited neuropeptide Y-induced feeding when neuropeptide Y (2.5 microg) and several doses of alpha-MSH were given simultaneously i.c.v. These results suggest that alpha-MSH plays an important role in the regulation of food intake of neonatal chicks.
Collapse
Affiliation(s)
- S Kawakami
- Department of Animal Production, Kyushu National Agricultural Experiment Station, 861-1192, Kumamoto, Japan
| | | | | | | | | | | | | |
Collapse
|
58
|
Denbow DM, Meade S, Robertson A, McMurtry JP, Richards M, Ashwell C. Leptin-induced decrease in food intake in chickens. Physiol Behav 2000; 69:359-62. [PMID: 10869603 DOI: 10.1016/s0031-9384(99)00258-9] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The effect of intracerebroventricular (i.c.v.) injection of leptin was investigated using broiler and Single Comb White Leghorn (SCWL)-type chickens. These represent relatively fast- and slow-growing birds, respectively. The i.c.v. injection of leptin decreased food intake in both broilers and Leghorns in a dose-dependent manner. The most efficacious dose appeared to be 10 microg in both types of chickens. Water intake was generally not affected by leptin, indicating that this effect was not due to general malaise. It appears that leptin can act within the central nervous sytstem of birds to decrease food intake.
Collapse
Affiliation(s)
- D M Denbow
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0306, USA.
| | | | | | | | | | | |
Collapse
|
59
|
Jenni L, Jenni-Eiermann S, Spina F, Schwabl H. Regulation of protein breakdown and adrenocortical response to stress in birds during migratory flight. Am J Physiol Regul Integr Comp Physiol 2000; 278:R1182-9. [PMID: 10801285 DOI: 10.1152/ajpregu.2000.278.5.r1182] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
During long-term fasting at rest, protein utilization is maintained at low levels until it increases at a threshold adiposity. This study examines 1) whether such a shift in energy substrate use also occurs during endurance exercise while fasting, 2) the role of corticosterone, and 3) the adrenocortical response to an acute stressor. Ten species of migrating birds caught after an endurance flight over at least 500 km were examined. Plasma uric acid and corticosterone levels were low in birds with fat stores >5% of body mass and high in birds with smaller fat stores. Corticosterone levels were very high in birds with no visible fat stores and emaciated breast muscles. Corticosterone levels increased with handling time only in birds with large fat stores. These findings suggest that 1) migrating birds with appreciable fat stores are not stressed by endurance flight, 2) a metabolic shift (increased protein breakdown), regulated by an endocrine shift (medium corticosterone levels), occurs at a threshold adiposity, as observed in birds at rest, 3) adrenocortical response to an acute stressor is inhibited after this shift, and 4) an adrenocortical response typical for an emergency situation (high corticosterone levels) is only reached when muscle protein is dangerously low.
Collapse
Affiliation(s)
- L Jenni
- Swiss Ornithological Institute, CH-6204 Sempach, Switzerland.
| | | | | | | |
Collapse
|
60
|
Horev G, Einat P, Aharoni T, Eshdat Y, Friedman-Einat M. Molecular cloning and properties of the chicken leptin-receptor (CLEPR) gene. Mol Cell Endocrinol 2000; 162:95-106. [PMID: 10854702 DOI: 10.1016/s0303-7207(00)00205-7] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The mammalian leptin receptor (LEPR) (formerly OB-R) mediates the weight regulatory effects of the circulating hormone leptin. The extreme obese phenotype of recessive mutations in the mouse leptin or LEPR genes (ob/ob and db/db mice, respectively) indicate the high potential of these genes for medical and agricultural research. In this paper, we report on the cloning of the full-length chicken leptin receptor (CLEPR) cDNA, which is the first non-mammalian cloning of a LEPR gene. The CLEPR gene shares a relatively low sequence similarity with its mammalian counterparts, with an average of 60% identical nucleotides. However, comparison between the predicted protein sequences has shown a tight conservation of most previously characterized LEPR motifs and essential tyrosine residues. Similarities between the chicken and the mammalian LEPR genes were also observed in the pattern of mRNA expression. The identification of the CLEPR gene should facilitate the study of the molecular mechanism involved in the regulation of body growth and composition in avian.
Collapse
Affiliation(s)
- G Horev
- Institute of Animal Science, Agricultural Research Organization, Volcani Center, Bet Dagan, Israel
| | | | | | | | | |
Collapse
|
61
|
Ohkubo T, Tanaka M, Nakashima K. Structure and tissue distribution of chicken leptin receptor (cOb-R) mRNA. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1491:303-8. [PMID: 10760595 DOI: 10.1016/s0167-4781(00)00046-4] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Chicken leptin receptor (cOb-R) cDNA has been cloned, sequenced and characterized. The predicted cOb-R preprotein was composed of 1148 amino acids showing approximately 60% sequence identity with the long isoform of mammalian leptin receptor, and contained a putative signal peptide, a single transmembrane domain and the conserved box 1, 2 and 3 motifs in the cytoplasmic region. High levels of cOb-R mRNA expression were observed in ovary and brain, and less abundant expression of the mRNA was detected in liver, kidney and intestine in juvenile females and sexually matured hens. The expression levels of cOb-R mRNA did not change during sexual maturation in most tissues, but the mRNA level in the intestine was higher in matured hens than in juveniles. Estrogen treatment was found to enhance the Ob-R mRNA expression in the intestine, but not in other tissues.
Collapse
Affiliation(s)
- T Ohkubo
- Center for Molecular Biology and Genetics, Department of Biochemistry, Faculty of Medicine, Mie University, Tsu, Mie, Japan
| | | | | |
Collapse
|
62
|
Baker DM, Larsen DA, Swanson P, Dickhoff WW. Long-term peripheral treatment of immature coho salmon (Oncorhynchus kisutch) with human leptin has no clear physiologic effect. Gen Comp Endocrinol 2000; 118:134-8. [PMID: 10753575 DOI: 10.1006/gcen.1999.7450] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effects of long-term peripheral exposure to recombinant human leptin were tested in immature coho salmon under both fed and fasted conditions. We found that high circulating levels of human leptin did not alter growth, energy stores, gonad weight, pituitary content of follicle-stimulating hormone, or plasma levels of insulin-like growth factor-I, insulin, growth hormone, or thyroxine.
Collapse
Affiliation(s)
- D M Baker
- School of Fisheries, University of Washington, Seattle, Washington, 98195, USA
| | | | | | | |
Collapse
|