The effect of clomiphene citrate on sex hormone binding globulin in normospermic and oligozoospermic men

The effect of clomiphene citrate (CC) on sex hormone binding globulin (SHBG) was studied in 10 oligozoospermic patients with varicocele and 6 normospermic men. Plasma SHBG, testosterone (T), oestradiol (E₂), FSH, LH. Prolactin (Prl), thyroxine (T₄) and 17-OH-progesterone (17-OH-P) were determined before and during medication. SHBG concentration rose from 38.1 ± 18.3 to 54.3 ± 16.0 nmol/l ( P < 0.01), while T and E₂ showed significant increases from 31.2 ± 10.8 nmol/***l and 24.6 ± 5.4 pg/ml to 52.0 ± 3.6 and 43.3 ± 14.9, respectively in the oligozoospermic patients, with similar rises noted in the normospermic men. FSH, LH and 17-OH-P were markedly elevated while on CC, but Prl and T₄ remained unchanged. The findings of this study indicated that CC causes an increase of SHBG concentration, which is probably related to the rise of E₂ concentration. This SHBG change, combined with the intrinsic oestrogenic activity of CC might be one of the factors responsible, through a decrease of free T and a T to E₂ imbalance, for the lack of a significant effect on parameters of seminal quality in so treated patients.