Effects of the H2 receptor antagonist ranitidine on anterior pituitary hormone secretion in man

The effect of an i.v. bolus of the H2-receptor antagonist ranitidine 50, 100, 200 and 300 mg on serum levels of prolactin, TSH, GH, LH, FSH and cortisol was studied in 12 normal males. Ranitidine 200 and 300 mg significantly stimulated prolactin release without affecting any of the other hormones. Ranitidine 300 mg caused a rise in prolactin comparable to that observed following cimetidine 200 mg. The results show that ranitidine releases prolactin in man, but only when a large intravenous injection is given.