Nature of changes in adrenocortical function in chronic hyperleptinemic female rats.

PERELLO M; MORENO G; CAMIHORT G; LUNA G; CONSOLE G; GAILLARD RC; SPINEDI E

ENDOCRINE

Humana Press

Año: 2004 vol. 24 p. 167 - 175

0969-711X

Neonatal treatment of rats with monosodium L-glutamate, which destroys hypothalamic arcuate nucleus neuronal bodies, induces several metabolic abnormalities; as a result, rats develop a phenotype of pseudo-obesity. This study was designed to explore, in the monosodium L-glutamate-treated female rat, the influence of chronic hyperleptinemia on adrenal cortex functionality. For this purpose, we evaluated in control and hypothalamic-damaged rats: a) in vivo and in vitro adrenocortical function, b) adrenal leptin receptor immuno-distribution and mRNA expression, and c) whether remains the inhibitory effect of leptin on adrenal function. Our results indicate that, compared to normal counterparts, pseudo-obese animals displayed: 1) hyperadiposity, despite being hypophagic and of lower body weight, 2) in vivo and in vitro enhanced adrenocortical response to ACTH stimulation, 3) an in vitro adrenal fasciculata-reticularis cell hyper-sensitivity to ACTH stimulus, 4) hyperplasia of their adrenal zona fasciculata cells, and 5) adrenal fasciculata-reticularis cells refractoriness to the inhibitory effect of leptin on ACTH-stimulated glucocorticoid production due, at least in part, to decreased adrenal leptin receptor expression. These data further support that increased hypothalamo-pituitary-adrenal axis function, in the adult neurotoxin-lesioned female rat, is mainly dependent on the development of both hyperplasia of adrenal zona fasciculata and adrenal gland refractoriness to leptin inhibitory effect. Our study supports that adrenal leptin resistance could be responsible, at least in part, for enhanced glucocorticoid circulating levels in this phenotype of obesity.