Different effects of cycloheximide and chloramphenicol on corticosterone production by isolated rat adrenal cells

Abstract

Cycloheximide and chloramphenicol both inhibit the stimulating effect of adenocorticotropic hormone (ACTH) on adrenal steroid production. To test whether these inhibitors had any effect on adrenal steroid production, independent from the mechanism of action of ACTH, we investigated their effect on the conversion of 25-hydroxycholesterol into corticosterone in isolated rat adrenal cells. Cycloheximide, both in the absence and in the presence of ACTH, had no effect on this conversion. Chloramphenicol inhibited the conversion of 25-hydroxycholesterol into corticosterone whether ACTH was present or not. The results with Cycloheximide indicate that ACTH has no direct effect on the cholesterol side-chain cleaving system. The inhibition by chloramphenicol of the ACTH-stimulated steroid production is at least partly due to inhibition of one or more of the processes involved in the conversion of 25-hydroxycholesterol into corticosterone.