Corticotropin-releasing hormone and calcium signaling in corticotropes.

Corticotropin-releasing hormone (CRH) stimulates ACTH secretion from anterior pituitary corticotropes, largely, but possibly not exclusively, via activation of the adenylyl cyclase cascade. CRH stimulates secretion by increasing Ca(2+) influx and by Ca(2+)-independent mechanisms. As Ca(2+) influx is largely regulated by membrane electrical properties, we review the effects of CRH on membrane excitability and changes in cytosolic Ca(2+). We also speculate on possible pathways for CRH modulation of exocytosis by Ca(2+) independent mechanisms.