Effects of synthetic gestagens on serum prolactin and growth hormone secretion in amenorrheic patients.

Abstract

Long-term application of synthetic gestagens to monkeys and dogs has been reported to induce benign hyperplasia and nodules in the mammary gland of these animals. The underlying mechanisms might be the increase of (GH) growth hormone serum concentrations observed after progestational steroid administration. Since (PRL) prolactin has been implicated in the etiology of human breast cancer this study was initiated to investigate the effect of synthetic gestagens on PRL and GH secretion in women. Amenorrheic women were treated with either (NG) norgestrel or (NETA) norethisterone acetate or (MPA) medroxyprogesterone acetate to induce withdrawal menstrual bleedings. Before and 7 days after gestagen therapy a standardized PRL stimulation test using (MTCL) metoclopramide was carried out. PRL as well as GH was measured by means of homologous radioimmunoassays. Gestagen application resulted in a significantly increased response of PRL after MTCL administration. Basal serum GH concentrations remained unaffected by such manipulations. The data presented indicate that gestagens might play a role in PRL secretion. If lactogenic hormones at all are involved in proliferative changes of the human mammary gland this might be rather due to alteration of PRL than GH secretion. (authors) (summary in GER)