Production of a growth factor by human spermatozoa
Abstract
We have previously shown that seminal plasma contains a putative growth promoting factor which was similar to transforming growth factor alpha. This study was conducted to show that sperm may have the ability to produce growth factors. Sperm conditioned media were subjected to sequential Sephadex G-75 (superfine) chromatography and high performance size exclusion liquid chromatography. The fractions were tested for mitogenic activity by the tritiated thymidine uptake assay, using rat granulosa cells and normal rat kidney (NRK) cells. Properties of the factor were established and partial characterization accomplished by gel electrophoresis. Mitogenic activity of sperm conditioned medium was not significantly affected in the presence of FSH, HCG, PRL, estradiol, testosterone, progesterone or dihydrotestosterone. The putative growth factor synergized with insulin-like growth factor-I (IGF- I), epidermal growth factor (EGF) and transforming growth factor-β (TGF-β) but not with TGF-α. The molecular weight of the factor as assessed by gel electrophoresis was 2 kDa.