Growth hormone and somatomedin C during post-menopausal replacement therapy with oestrogen alone and in combination with an antioestrogen.

Serum concentrations of growth hormone (GH) and somatomedin C were monitored in 14 women during post-menopausal replacement therapy with oestrogen alone and in combination with a specific antioestrogen. During 3 mth of treatment with ethinyl oestradiol (10 micrograms daily), the mean serum GH level rose from 2.8 +/- 0.78 mU/l (mean +/- S.E.M.) to 6.5 +/- 0.39 mU/l, whereas the concentration of somatomedin C fell from 22.4 +/- 0.89 to 15.4 +/- 0.43 nM. These changes during unopposed oestrogen treatment were clearly reversed by the addition of tamoxifen (20 mg daily), following which GH concentrations fell to pre-treatment levels. It is suggested that oestrogens inhibit somatomedin C production in the liver and that GH secretion may play an important role in regard to certain liver effects induced by oral oestrogen therapy.