CLINICAL STUDY Discontinuation of estrogen replacement therapy in GH-treated hypopituitary women alters androgen status and IGF-I

Objective and design: Compared with their male counterparts, healthy females secrete more growth hormone (GH) and those with GH-deficiency have lower insulin-like growth factor I (IGF-I) levels and are less responsive to GH substitution. To test whether this gender difference is related to sex hor-mones we measured androgen status and IGF-I related parameters in 38 hypopituitary women (mean (range) age 41.5 (20–58) years) during continued GH substitution as compared with a control group of 38 healthy women matched for age and menopausal status. Twenty six patients were studied twice: with estrogen replacement and after 28 days of estrogen discontinuation in a randomised design. Results: The patients were androgen deficient compared with controls (median, range), dehydroepian-drosterone sulphate (DHEAS): 185 (99 –7800) nmol/l vs 4400 (820–13 000) nmol/l, P ,0.001; androstenedione: 0.5 (0.1 –7.1) nmol/l vs 4.3 (1.6 –8.8) nmol/l, P ,0.001; dihydrotestosterone (DHT): 0.13 (0.09–0.54) nmol/l vs 0.55 (0.09–0.89) nmol/l, P ,0.001; testosterone: 0.28 (0.09–1.56) nmol/l vs 1.1 (0.71–2.24) nmol/l, (P ,0.001); free testosterone: 0.004 (0.001– 0.030) nmol/l vs 0.016 (0.001–0.030) nmol/l, P ,0.001. The circulating levels of IGF-I, IGF-II, IGF-binding protein 1 (IGFBP-1), and IGFBP-3 did not differ between patients and controls. Th