How is biosynthesis of aldosterone compartmentalized and regulated within the cell?

 

Angiotensin 2 but not ACTH, increases expression of StAR and P450scc in the zona glomerulosa of the adrenal cortex leading to enhanced uptake of cholesterol and conversion to pregnenolone. Pregnenolone diffuses out of the mitochondria and into the SER but since P450c 17 is not expressed in the zona glomerulosa, pregnenolone is converted to progesterone by 3 beta HSD in the SER membrane.

Progesterone is converted to the mineralocorticoid 11-deoxycorticosterone by P450c21 in the SER. DOC diffuses out of the SER and into the mitochondria, where it is converted sequentially to corticosterone and then to aldosterone by P450aldo. Aldosterone than diffuses out of the cell.