Plasma concentrations of pituitary and peripheral hormones during ranitidine treatment for two years in men with duodenal ulcer.

The effects of treatment for 2 years with the histamine H2-receptor antagonist ranitidine (100 or 200 mg b.d. for 6 weeks followed by 100 or 200 mg daily) on plasma concentrations of pituitary and peripheral hormones in ten men with duodenal ulcer have been investigated. Stimulation tests with TRH 200 micrograms i.v. and LHRH 100 micrograms i.v. were performed before, during (6 and 24 months), and at least 6 months after treatment. Basal and TRH-stimulated prolactin (PRL) secretion was marginally reduced after treatment for 6 months, but not for 24 months. The LH response to LHRH was slightly increased after treatment for 6 months and 24 months and after the end of treatment. The plasma concentrations of TSH, FSH, cortisol, androgenic hormones, and thyroid hormones did not change significantly during treatment. No adverse effects were reported during the observation period. The few, minor changes in pituitary hormone concentrations were all within the reference range. They may be related to ranitidine treatment, but are more likely to be due to age-dependent alterations in hormone secretion. It is concluded that long-term treatment with ranitidine does not cause major changes in circulating hormone concentrations.