Localization of the gene transcripts of 11 beta-hydroxylase and aldosterone synthase in the rat adrenal cortex by in situ hybridization.

Using in situ hybridization, localization of the gene transcripts of 11 beta-hydroxylase and aldosterone synthase was investigated in order to clarify the sites for the synthesis of corticosterone (glucocorticoid) and aldosterone (mineralocorticoid) in the rat adrenal cortex. The gene transcript of 11 beta-hydroxylase was localized in all the endocrine cells of the entire adrenal cortex, while that of aldosterone synthase was exclusively confined in zona glomerulosa cells. These results represent that every endocrine cell of all the cortical zones synthesizes 11 beta-hydroxylase which converts 11-deoxycorticosterone to corticosterone, and only glomerulosa cells synthesize aldosterone synthase which produces aldosterone from corticosterone. Thus it is clearly shown that zona glomerulosa cells synthesize mineralocorticoid, while zona fasciculata as well as reticularis cells produce glucocorticoid.