Effect of morphine on the hypothalamic-pituitary axis in postmenopausal women

In this study, 10 postmenopausal women were given 5 mg of morphine intravenously; and the serum level of prolactin (PRL), luteinizing hormone (LH), follicle-stimulating hormone (FSH), and growth hormone (GH) were measured before and after morphine injection. A significant increase in serum prolactin as well as a significant decrease in LH were observed following the administration of morphine. It is suggested that morphine may affect a common neurotransmitter that controls both prolactin and LH secretion. It is also of interest that the increase in serum prolactin following morphine injection is of similar magnitude as observed in premenopausal patients.