The adrenal gland is implicated in energy homeostasis, and dysfunction of this gland contributes to a variety of metabolic disorders including the development of hypertension, diabetes, osteoporosis, and obesity. Recently, adipokines have been implicated in adrenal function. Adiponectin, an adipokine, with insulin sensitising and anti-inflammatory properties, exerts its effects by activating two distinct seven transmembrane domain receptors, adiponectin-R1 (adipoR1) and -R2 (adipoR2). In this study, we investigated the expression of adiponectin receptors in the human fetal and adult adrenal gland, as well as in the leptin deficient obese (ob/ob) mouse.
Using RT-PCR, we demonstrate for first time the expression of both receptors in both fetal and adult adrenal glands as well as in a human adrenocortical cell line (NCI-H295R) at mRNA level. Immunofluorescent analysis of fetal adrenals (10, 20, 23 wk and 10wk anencephalics) demonstrated that that protein expression of adipoR1 and adipoR2 is associated with cells that have steroidogenic activity.Using real-time PCR, mRNA expression of both receptors in adrenal glands of the leptin deficient obese mouse (ob/ob) were found to be increased compared to the lean wt mouse. Moreover, there was a positive correlation between the extent of obesity and the level of adipoR1 but not adipoR2 expression.
In conclusion, specific expression of both adiponectin receptors in the steroid secreting zones of human fetal and adult adrenals, as well as in the obese mouse model, signifies a putative role for adiponectin and steroidogenesis, and its potential implications in the development of metabolic disorders associated with adrenal dysfunction.
04 - 06 Apr 2005
British Endocrine Societies