Intracerebroventricular infusion of leptin elevates the secretion of luteinising hormone without affecting food intake in long-term food-restricted sheep, but increases growth hormone irrespective of bodyweight

被引:123
作者
Henry, BA
Goding, JW
Tilbrook, AJ
Dunshea, FR
Clarke, IJ
机构
[1] Prince Henrys Inst Med Res, Clayton, Vic 3168, Australia
[2] Monash Univ, Sch Med, Dept Pathol & Immunol, Prahran, Vic 3181, Australia
[3] Monash Univ, Dept Physiol, Clayton, Vic 3168, Australia
[4] Victorian Inst Anim Sci, Werribee, Vic 3030, Australia
关键词
D O I
10.1677/joe.0.1680067
中图分类号
R5 [内科学];
学科分类号
1002 ; 100201 ;
摘要
Leptin can act as a satiety factor and exert neuroendocrine effects, but most studies have been performed in fasted animals. We aimed to determine the effect of chronic under-nutrition on the response to a 3-day intracerebroventricular infusion of leptin with regard to food intake and the secretion of pituitary hormones. Ovariectomised ewes (n=6) had a mean (+/- S.E.M..) bodyweight of 56 +/- 0.8 kg on a diet available ad libitum (ad Iib) or 33.4 +/- 1 kg on a restricted diet. The differential bodyweight was achieved by dietary means over a period of 6 months prior to the commencement of the study. Leptin (4 mug/h) or vehicle (artificial cerebrospinal fluid (aCSF)) was infused into the third cerebral ventricle for 3 days. Blood samples were taken prior to commencement and on day 3 of infusion for the assay of plasma hormone levels. The experiment was repeated one week later in a crossover design. Food intake and metabolic status were monitored daily. The luteinising hormone (LH) pulse amplitude was lower (P<0.05) but plasma growth hormone (GH) levels were higher (P<0.05) in the food-restricted animals. Plasma levels of glucose, lactate, insulin, urea and triglycerides were similar in the two groups but nonesterified fatty acid levels were higher (P<0.01) in the animals on an ad Iib diet. Leptin reduced (P<0.05) food intake only in the animals fed an ad lib diet. Leptin increased (P<0.05) the secretion of LH in the food-restricted group only and increased (P<0.05) GH irrespective of bodyweight. In conclusion, leptin does not alter food intake in animals on a restricted diet but can increase the secretion of LH in the same animals. The treatment of leptin was not sufficient to reduce plasma GH levels in the food-restricted animals, suggesting that other factors or mechanisms must be involved in the regulation of this axis.
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收藏
页码:67 / 77
页数:11
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[1]   Effect of chronic food restriction on pulsatile luteinizing hormone secretion and hypothalamic neuropeptide Y gene expression in castrate male sheep [J].
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Young, P ;
Mercer, JG .
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[2]   Leptin regulation of neuroendocrine systems [J].
Ahima, RS ;
Saper, CB ;
Flier, JS ;
Elmquist, JK .
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[3]   Role of leptin in the neuroendocrine response to fasting [J].
Ahima, RS ;
Prabakaran, D ;
Mantzoros, C ;
Qu, DQ ;
Lowell, B ;
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NATURE, 1996, 382 (6588) :250-252
[4]   CONTROL OF FEED-INTAKE AND REGULATION OF ENERGY-BALANCE IN RUMINANTS [J].
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[5]   Recombinant porcine leptin reduces feed intake and stimulates growth hormone secretion in swine [J].
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Yan, X ;
Azain, MJ ;
Kraeling, RR ;
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Ramsay, TG .
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[6]   Increased galanin and neuropeptide-Y immunoreactivity within the hypothalamus of ovariectomised ewes following a prolonged period of reduced body weight is associated with changes in plasma growth hormone but not gonadotropin levels [J].
BarkerGibb, ML ;
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[7]   THE ROLE OF NEUROPEPTIDE-Y (NPY) IN THE CONTROL OF LH-SECRETION IN THE EWE WITH RESPECT TO SEASON, NPY RECEPTOR SUBTYPE AND THE SITE OF ACTION IN THE HYPOTHALAMUS [J].
BARKERGIBB, ML ;
SCOTT, CJ ;
BOUBLIK, JH ;
CLARKE, IJ .
JOURNAL OF ENDOCRINOLOGY, 1995, 147 (03) :565-579
[8]   EFFECTS OF OBESITY ON INSULIN SENSITIVITY AND RESPONSIVENESS IN SHEEP [J].
BERGMAN, EN ;
REULEIN, SS ;
CORLETT, RE .
AMERICAN JOURNAL OF PHYSIOLOGY, 1989, 257 (05) :E772-E781
[9]   FEEDBACK EFFECTS OF THE TESTIS ON PITUITARY-RESPONSIVENESS TO LUTEINIZING-HORMONE-RELEASING HORMONE INFUSIONS IN THE RAM [J].
BREMNER, WJ ;
FINDLAY, JK ;
LEE, VWK ;
DEKRETSER, DM ;
CUMMING, IA .
ENDOCRINOLOGY, 1980, 106 (01) :329-336
[10]   RECOMBINANT MOUSE OB PROTEIN - EVIDENCE FOR A PERIPHERAL SIGNAL LINKING ADIPOSITY AND CENTRAL NEURAL NETWORKS [J].
CAMPFIELD, LA ;
SMITH, FJ ;
GUISEZ, Y ;
DEVOS, R ;
BURN, P .
SCIENCE, 1995, 269 (5223) :546-549