Polyhormonal regulation of avian and mammalian corticosteroidogenesis in vitro.

1. The combined actions of ACTH, corticosterone and prolactin (PRL) in the acute regulation of corticosteroidogenesis were investigated using isolated adrenocortical cells from intact and hypophysectomized (hypox) rats (Rattus norvegicus) and from intact male domestic fowl (Gallus gallus domesticus). 2. Exogenous corticosterone suppressed to about 50% ACTH-induced corticosterone production of cells from either species. This suppression, in part, was due to corticosterone degradation. 3. oPRL, in the presence or absence of ACTH, raised corticosterone production of hypox rat cells, but not intact rat and domestic fowl cells. 4. In addition, oPRL counteracted the corticosterone-induced suppression of net ACTH-stimulated corticosterone production of hypox rat and intact domestic fowl cells, but not intact rat cells. 5. The potency of oPRL with domestic fowl cells was 4 times that with hypox rat cells. 6. Furthermore, in domestic fowl cells, the effect of oPRL was Ca2+-dependent.