Steroid biosynthesis in a feminizing adrenal carcinoma

Minced tissue from a feminizing adrenal carcinoma was incubated for 1 hr with cofactors and equimolar amounts of 7α-3H-pregnenolone and 4-14C-progesterone. Seventeen compounds were isolated and recrystallized to constant specific activity. The isotopic ratios indicated that the conversion of pregnenolone to progesterone was negligible and that 3H in 17-hydroxyprogesterone came primarily by way of 17-hydroxypregnenolone. The 16-hydroxy derivatives of progesterone, testosterone and androstenedione were derived exclusively from 14C-progesterone, as were desoxycorticosterone, corticosterone, corticosterone, compound A and aldosterone. Pregnenolone gave rise to a high proportion of isotopically labeled 17-hydroxyprogesterone, testosterone, 2-hydroxytestosterone and estrone. The series 17-hydroxyprogesterone→compound S→cortisol→Reichstein's V showed a 3H/14C ratio which decreased successively: 12.2, 8.1, 6.5, 2.6. All these findings confirm the predominant role of pregnenolone as precursor for C19 and ...