Extracellular ATP potentiates steroidogenic effect of adrenocorticotropic hormone in bovine adrenocortical fasciculata cells

We examined the effect of extracellular adenosine 5'-triphosphate (ATP) on adrenocorticotropic hormone (ACTH)- and angiotensin II-induced steroidogene sis in bovine adrenocortical fasciculata cells. The low concentration of AT P (5 muM) potentiated ACTH-induced steroidogenesis synergistically. However , the purine derivative did not affect angiotensin II-induced steroidogenes is. Although adenosine (100 muM) (a metabolite of ATP) showed a weak steroi dogenic effect, it did not potentiate ACTH-induced steroidogenesis. ATP als o enhanced the steroidogenesis by NaF synergistically in bovine adrenocorti cal cells, but did not potentiate forskolin- and dibutyryl cyclic AMP-induc ed steroidogenesis. The stimulating effect of ACTH on cyclic AMP production was synergistically accelerated by ATP (5 muM), which has no effect by its elf on cyclic AMP formation. These results suggest that extracellular ATP a ffected the ACTH receptor-adenylyl cyclase coupling processes, and potentia tion of steroidogenesis by ACTH ensued in bovine adrenocortical fasciculata cells.