RELEASE OF BETA-ENDORPHIN FROM RAT PITUITARY INVITRO

The rate of release of β-endorphin immunoreactivity from the anterior lobe of the rat pituitary in vitro increased in response to potassium-induced depolarization in a calcium-dependent manner. Potassium-induced depolarization did not, however, change the rate of release from intermediate/posterior lobe. These findings provide support for the view that β-endorphin may have a humoral function and suggest that β-endorphin stores in discrete pituitary areas are regulated by different release mechanisms. © 1978.