Effect of exogenous beta-endorphin on anterior pituitary hormone secretion in man

The effect of large amounts of synthesized human beta-endorphin (beta-EP) administered intrathecally on pituitary-adrenocortical function was investigated by determining the plasma levels of ACTH, cortisol, growth hormone and prolactin in 8 patients with pain caused by severe disseminated cancer. They were divided into 2 groups, an Ep group of 8 patients and a control group of 5 of the same 8 patients. There were no significant effects of beta-Ep on plasma ACTH, cortisol and growth hormone levels. However, the injection of beta-Ep into human subjects resulted in a rise in plasma concentrations of prolactin.