Localization and differential expression of adenylyl cyclase messenger ribonucleic acids in rat adrenal gland determined by in situ hybridization

The expression of adenylyl cyclases (ACs) in the adult rat adrenal gland was examined. In situ hybridization revealed specific patterns of AC messenger RNA (mRNA) distribution. AC1 was limited exclusively to the adrenal medulla. AC5 and AC6 were mainly expressed in the adrenal medulla, with a weak expression in the zona glomerulosa. AC9 was found in all the three regions of the adrenal cortex but not in the adrenal medulla. All these ACs were detected on postnatal day 1 (PN1), and their pattern of expression was unchanged on PN7, PN21, and PN90 (adult). We analyzed the response of these ACs to various physiological conditions known to affect the synthesis of aldosterone and corticosterone in the adrenal cortex. Our study demonstrates a specific increase of AC6 but not AC5 mRNA in the zona glomerulosa of rats given a low sodium diet. AC9 mRNA was increased in all the three cortical zones of rats treated with ACTH. We suggest that AC6 and AC9 play important roles in different pathways associated with the regulation of aldosterone and corticosteroid production.