Central infusion of leptin into well-fed and undernourished ewe lambs: effects on feed intake and serum concentrations of growth hormone and luteinizing hormone
| Autor: | N Raver, Jean Djiane, Jay A Daniel, B J Holmberg, Duane H. Keisler, C D Morrison, Arieh Gertler |
|---|---|
| Přispěvatelé: | ProdInra, Migration, Unité de biologie cellulaire et moléculaire, Institut National de la Recherche Agronomique (INRA) |
| Předmět: |
Leptin
LH medicine.medical_specialty medicine.drug_class Endocrinology Diabetes and Metabolism medicine.medical_treatment media_common.quotation_subject [SDV]Life Sciences [q-bio] Adipose tissue Sheep Diseases Biology Growth hormone 03 medical and health sciences Eating Endocrinology Internal medicine medicine Animals Insulin ComputingMilieux_MISCELLANEOUS 030304 developmental biology media_common 2. Zero hunger 0303 health sciences Sheep digestive oral and skin physiology 0402 animal and dairy science 04 agricultural and veterinary sciences Luteinizing Hormone 040201 dairy & animal science Nutrition Disorders [SDV] Life Sciences [q-bio] Growth Hormone Ovariectomized rat Animal Nutritional Physiological Phenomena Female Reproduction Gonadotropin Luteinizing hormone hormones hormone substitutes and hormone antagonists |
| Zdroj: | ResearcherID Journal of Endocrinology Journal of Endocrinology, BioScientifica, 2001, 168, pp.317-324 |
| ISSN: | 0022-0795 1479-6805 |
| Popis: | Leptin has been implicated in the regulation of feed intake, growth, and reproduction. The objective of this study was to determine if centrally administered leptin would affect feed intake and the secretion of growth hormone (GH) and luteinizing hormone (LH) in ewe lambs. Eighteen ewe lambs were ovariectomized and fitted with intracerebroventricular (i.c.v.) cannulae. Lambs were randomly assigned to receive either a maintenance diet (fed), or a diet that provided 38% of maintenance requirements (diet-restricted) for 14 weeks. Subsequently, recombinant ovine leptin or vehicle was continuously infused, via i.c.v. cannulae, in a linearly increasing dose for 8 days, reaching a maximum of 1.25 microg/kg per h. Feed intake was recorded on days -1 to 7. Blood was collected via jugular cannulae every 10 min for 4 h on days 0, 2, 4, 6 and 8 for the determination of serum leptin, insulin, LH and GH. Leptin suppressed feed intake in fed lambs on days 4 to 7 (P0.25). Fed lambs had greater serum concentrations of leptin than diet-restricted lambs (P=0.007). Also, although not different on day 0 (pretreatment), on day 8 serum leptin concentrations were greater in leptin-treated lambs than in saline-treated lambs (P=0.003). Insulin was lower in diet-restricted than in fed lambs (P=0.003), but was not affected by leptin treatment (P=0.82). LH pulse frequencies were lower in diet-restricted lambs than in fed lambs (P=0.038), but were not affected by leptin treatment (P=0.85). Mean serum GH was greater in diet-restricted than in fed lambs (P0.32). From this work, we propose that leptin represents an important functional link between adipose stores and hypothalamic function in ruminants. We demonstrate that leptin concentrations change in response to reduced nutritional status, and that leptin has the ability to regulate multiple physiological processes in lambs, including both feed intake and secretion of GH. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|