3 Beta-hydroxysteroid dehydrogenase-isomerase activity in bovine adrenocortical cells in culture: lack of response to ACTH treatment.

Primary cultures of bovine adrenocortical cells (BAC) were used to determine whether the adrenal microsomal 3 beta-hydroxysteroid dehydrogenase-isomerase complex (3 beta-HSD), like the 17 alpha-hydroxylase (17-OHase), responded to ACTH treatment with an increase in activity. Both enzymes influence the steroidogenic path leading to 17 alpha-hydroxyprogesterone formation and thus could affect adrenal androgen biosynthesis. 3 beta-HSD Activity in postmitochondrial supernatant fluid, homogenates or cell monolayers remained unchanged after cells had been maintained in 1 microM ACTH up to 48 h. Since ACTH exposure led to a marked increase in 17-OHase activity over the same time period, it is concluded that, under the conditions used, the 3 beta-HSD-isomerase complex in BAC is nonresponsive to tropic hormone treatment.