BIOCHEMISTRY OF HISTOLOGICALLY DEFINED ZONES IN THE ADRENAL CORTEX: CORTISOL SYNTHESIS IN THE HORSE

Publisher Website
Google Scholar
Abstract
SUMMARY: The ability of cells from the zona fasciculata and zona reticularis of the horse adrenal cortex to transform [7α-3H]pregnenolone, [4-14C]progesterone, [7α-3H]17α-hydroxypregnenolone and [4-14C]17α-hydroxyprogesterone to cortisol in vitro was investigated. It was found that: (1) Both types of cell form cortisol from these steroids. (2) The transformation is greater in fascicular cells. (3) The formation of 17α-hydroxyprogesterone from pregnenolone (via either progesterone or 17α-hydroxypregnenolone) is slower that the subsequent formation of cortisol from 17α-hydroxyprogesterone. (4) The formation of 17α-hydroxyprogesterone from 17α-hydroxypregnenolone is rate-limiting in cortisol formation, but is about 2·4 times faster in fascicular than in reticular cells. (5) 17α-Hydroxylation of progesterone is also faster in fascicular than in reticular cells.