An association between testicular function and vasoconstrictive peptide endothelin-1 levels, which is produced by Leydig and Sertoli cells, is observed. Endothelin 1 regulates blood flow in the testis and stimulates testosterone secretion.
The purpose of this study is (1) to estimate the influence of tamoxifene and raloxifene therapy on enthothelin-1 levels in men of reproductive age with idiopathic hypogonadism. (2) To find an association between improvement of semen parameters and changes of peptide levels during therapy.
Materials and methods: Forty men (40) with idiopathic hypogonadism were studied. Group 1 consisted of twenty (20) men aged 35±4.4 yrs who received tamoxifen therapy (20 mg/day for three months). Group 2 consisted of twenty (20) men aged 34.1±4.3 yrs who received raloxifene therapy (60 mg/day for three months). Endothelin-1 levels were measured before and three months after initiation of therapy. All patients had a semen analysis at the same times.
Results: 1 Tamoxifene therapy improved morphology and movement of spermatozoa significantly whereas raloxifene therapy improved the number and morphology of spermatozoa. 2) Endothelin-1 levels didnt differ significantly between the two groups before therapy (58.6±27.4 pg/ml vs 46.7±25.4 pg/ml respectively) 3) Tamoxifene increased levels of endothelin-1 but not significantly(58.6±27.9 pg/ml vs 76.3±26.2 pg/ml). 4) Raloxifene did not alter endothelin-1 levels (46.7±25.4 pg/ml vs 46.9±28.2 pg/ml). 5) After three months of therapy, endothelin-1 levels were higher in men in group 1 than the ones in group 2. 6) No association was found between enthothelin-1 levels and semen parameteres before and three months after therapy.
Conclusions: The present study shows that tamoxifene tends to increase endothelin-1 levels and this action is not observed after raloxifene therapy. Furthermore, small changes in endothelin-1 levels are not associated with improvement of semen parameters after therapy with either of the two medications (tamoxifene and raloxifene).
01 - 05 Apr 2006
European Society of Endocrinology