Food intake-induced leptin secretion modulates hypothalamo-pituitary-adrenal axis response and hypothalamic Ob-Rb expression to insulin administration

Details

Serval ID
serval:BIB_2E71BFD26672
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Food intake-induced leptin secretion modulates hypothalamo-pituitary-adrenal axis response and hypothalamic Ob-Rb expression to insulin administration
Journal
Neuroendocrinology
Author(s)
Giovambattista  A., Chisari  A. N., Gaillard  R. C., Spinedi  E.
ISSN
0028-3835 (Print)
Publication state
Published
Issued date
12/2000
Volume
72
Number
6
Pages
341-9
Notes
Journal Article
Research Support, Non-U.S. Gov't --- Old month value: Dec
Abstract
The mutation of the ob gene is known to induce a phenotype of obesity accompanied by symptoms including enhanced production of glucocorticoid. Chronic administration to ob/ob mice of leptin, the ob gene product, reverses hypercorticosteronemia. This establishes a clear relation between adipocyte and hypothalamo-pituitary-adrenal (HPA) axis functions. In the present study we investigated the acute modulatory effects of food intake-stimulated leptin secretion on HPA axis activity and hypothalamic leptin receptor (Ob-Rb) expression in 24-hour fasting, adult female, BALB/c mice after insulin-induced hypoglycemia. Our results indicate that: (1) food supply for 45 min to 24-hour fasting mice increased plasma glucose levels and reversed both hypercorticosteronemia and hypoleptinemia; (2) the insulin-induced hypoglycemia produced a marked HPA axis activation in animals with no access to food but this response was fully prevented by food intake and the consecutive increase in plasma leptin levels; (3) the inhibitory effect of leptin on the HPA axis response to insulin-induced hypoglycemia was corroborated by i.p. administration of murine leptin, and (4) fasting-induced hypothalamic Ob-Rb overexpression is not modulated by insulin itself but by leptin, since increase in leptin levels by food intake or by administration of exogenous leptin completely reversed this Ob-Rb overexpression. These results confirm the inhibitory effect of leptin on the HPA axis response to various stress stimuli. They clearly demonstrate that acute food intake in 24-hour fasting mice: (a) rapidly reduced fasting-induced hypercorticosteronemia by enhancing both spontaneous and insulin-elicited endogenous leptin secretion; (b) fully prevented HPA axis response to insulin administration, by rapidly increasing endogenous leptin secretion and probably also by diminishing the extent and the duration of insulin-induced hypoglycemia, and (c) abolished hypothalamic Ob-Rb overexpression induced by fasting itself combined with insulin treatment. The present data strongly suggests an inhibitory effect of endogenous leptin on insulin-induced HPA axis response, an interaction relevant to the physiological adaptation to starvation and caloric excess, and further supports the pivotal role played by the hypothalamus in restoring homeostasis in different allostatic states.
Keywords
Adrenocorticotropic Hormone/blood Animals Blood Glucose Carrier Proteins/*genetics Eating/*physiology Energy Metabolism/physiology Fasting/physiology Female Gene Expression/drug effects/physiology Homeostasis/drug effects/physiology Hypoglycemic Agents/*pharmacology Hypothalamo-Hypophyseal System/drug effects/*metabolism/secretion Insulin/*pharmacology Leptin/blood/*secretion Mice Mice, Inbred BALB C Pituitary-Adrenal System/drug effects/*metabolism/secretion RNA, Messenger/analysis *Receptors, Cell Surface Stress/metabolism
Pubmed
Web of science
Create date
15/02/2008 16:57
Last modification date
20/08/2019 13:13
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