β-Endorphin alters luteinizing hormone secretion via the amygdala but not the hypothalamus

Abstract

Morphine and enkephalins are able to alter pituitary hormone secretion. It has been postulated that they do not act directly at the pituitary, but rather that the hypothalamus is the site at which inhibition or stimulation of pituitary hormone secretion is initiated. On the other hand, endogenous opiates have been located in distinctly different neuronal regions, including areas outside the hypothalamus. The effects of beta-endorphin on plasma luteinizing hormone (LH) levels have not been explored, and the present experiments attempt to elucidate the contribution and the possible site of action of beta-endorphin in the control of LH secretion. The results show that beta-endorphin inhibits pituitary LH secretion if applied into the amygdala but not when given into the hypothalamus.