High resolution

Module 10: Figure corticotroph regulation

Regulation of ACTH secretion by corticotrophs.

Release of adrenocorticotropic hormone (ACTH) is regulated by corticotropin-releasing factor (CRF) that acts through the cyclic AMP signalling pathway to induce the firing of regular action potentials (APs). The latter are responsible for opening L-Type (L) voltage-operated Ca2+ channels that generate the Ca2+ signals responsible for triggering the release of ACTH. Cyclic AMP acting through protein kinase A (PKA) also activates the gene for pro-opiomelanocortin (POMC), which is the precursor of ACTH. Cortisol acts through the glucocorticoid receptor (GR) to inhibit POMC transcription.