Pregnenolone Metabolism in an Aldosterone Secreting Tumor of the Adrenal and Its Adjacent Adrenal Tissue

The metabolism of pregnenolone-7α-3H has been studied in vitro in an aldosterone producing tumor and in the adrenal tissue adjacent to the tumor. The predominant products in the incubation of the tumor tissue were progesterone, and lesser amounts of deoxycorticosterone and aldosterone, with no cortisol. The adjacent adrenal tissue converted pregnenolone to androstenedione and cortisol, with no aldosterone. Although 17-oxygenated steroids were produced by both tissues, the tumor failed to convert 17-hydroxyprogesterone to 11-deoxycortisol or cortisol. Androstenedione was formed in the tumor incubation but was not converted to an 11-hydroxylated product. These findings suggest that the biosynthetic pathways in the aldosterone secreting tumor were directed both by the presence of 18-hydroxylase system and by the relative absence of alternate pathways leading to cortisol or androgen synthesis.