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 gla nd was examined. In situ hybridization revealed specific patterns of A C messenger RNA (mRNA) distribution. AC1 was limited exclusively to th e adrenal medulla. AC5 and AC6 were mainly expressed in the adrenal me dulla, with a weak expression in the zona glomerulosa. AC9 was found i n all the three regions of the adrenal cortex but not in the adrenal m edulla. All these ACs were detected on postnatal day 1 (PN1), and thei r pattern of expression was unchanged on PN7,PN21, and PN90 (adult). W e analyzed the response of these ACs to various physiological conditio ns 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 di et. AC9 mRNA was increased in all the three cortical zones of rats tre ated with ACTH. We suggest that AC6 and AC9 play important roles in di fferent pathways associated with the regulation of aldosterone and cor ticosteroid production.