Calcium ion as "second messenger" in corticoidogenic action of ACTH.

Abstract

The correlation between corticoidogenesis and Ca2+-influx in the cell was investigated using isolated rat or bovine adrenocortical cells. ACTH-induced corticoidogenesis in rat and bovine adrenocortical cells was enhanced in parallel with increasing concentrations of external Ca2+. In the bovine but not in the rat cells the marked stimulatory effect of external Ca2+ on the corticoidogenesis was observed despite the absence of ACTH. Ca2+-influx and corticoidogenesis always occurred simultaneously. Verapamil markedly inhibited corticoidogenesis or Ca2+-influx in response to ACTH. The stimulatory effect of Ca2+ on corticoidogenesis was completely blocked by cycloheximide. Ca2+ possibly could regulate corticoidogenesis as a primary second messenger of ACTH through biosynthesis of so-called steroidogenic protein.