Hydroxylation of Steroids by the Isolated Rat Adrenal

When 11-deoxycorticosterone was added to the incubation medium of isolated, quartered rat adrenals in the absence of ACTH, 21 % was converted to corticosterone. 10% to the 20 → 18-hemiketal of 18-hydroxy-11-deoxycorticosterone and 3 % to material with a mobility relative to corticosterone (R B ) of 0.10 in the toluene-propylene glycol system. The corresponding figures obtained with progesterone were 11%, 4% and 2% respectively. The addition of 18-hydroxyprogesterone caused an increase in the production of the 20 → 18-hemiketal of 18-hydroxy-11-deoxycorticosterone, which accounted for 6 % of the added steroid; it also caused the formation of an unidentified compound of RB 1.13 that did not reduce tetrazolium and yielded an absorption maximum in methanol at 240 mμ. Corticosterone only increased the formation of material with R B 0.10. The recovery of aldosterone was not affected by any of the added steroids. The conversion of added steroids was either unaffected or inhibited by ACTH.