Leptin and the adrenal gland

Background Leptin is involved in the maintenance of energy balance acting o n food intake, thermogenesis and energy expenditure. Via its receptor in th e hypothalamus, leptin modulates the functioning of the hypothalamic-pituit ary-adrenal axis and the systemic sympathetic/adrenomedullary system, which are closely linked to the regulation of energy balance and body weight. In regard of potential interactions of leptin and adrenal hormones this study intended to characterize the role of leptin in the human adrenal gland. Materials and methods A novel technique of laser capture microdissection wa s used to separate cortical and chromaffin cells for mRNA expression studie s of leptin receptor isoforms and leptin mRNA in adrenal tissue and cell li ne NCI-H295. Immunostaining was used to localize leptin receptor in human a drenal slices. The influence of leptin on basal and ACTH-stimulated steroid hormone secretion and enzyme expression was assessed. The effect of leptin on proliferation and viability of adrenal cells in primary culture and of the NCI-H295 cell line was studied by the WST-1 assay and by H-1-thymidine test. Results Our data demonstrate that leptin can regulate the human adrenal fun ction directly, via its receptors on adrenocortical cells. Leptin decreased the corticotropin-stimulated release of steroid hormones In vitro without any effect on cell proliferation. No influence of leptin on the expression of cytochrome P450(17 alpha) and P450(SCC) mRNA was detected. Conclusions The adipo-adrenal interaction mediated by leptin further unders cores the close link of metabolism and stress regulation in humans.