IDENTIFICATION OF A TRANSFORMING GROWTH-FACTOR ALPHA-LIKE MOLECULE HUMAN SEMINAL PLASMA

Objective: To characterize the putative seminal growth promoting facto r serendipitously observed when human seminal plasma was analyzed for bioactive FSH. Design: A pool of human seminal plasma was subjected to sequential Sephadex G-75 (superfine) chromatography and high-performa nce size exclusion liquid chromatography. The fractions were tested fo r mitogenic activity using a rat granulosa cell assay and normal rat k idney (NRK) cells. Properties of the factor were established and chara cterization by gel electrophoresis and neutralization with antibody we re accomplished. Setting: Reproductive Biology Research Laboratory at McMaster University Medical Centre. Main Outcome Measures: Ability of purified fractions of human seminal plasma to augment the uptake of tr itiated thymidine into cell DNA. Results: Mitogenic activity of human seminal plasma was augmented in the presence of FSH but not hCG, PRL, E(2), T, P, or dihydrotestosterone. The putative growth factor synergi zed with insulin-like growth factor I (IGF-I), epidermal growth factor (EGF), and transforming growth factor beta (TGF-beta) but not with TG F-alpha. Mitogenic activity was neutralized by a specific TGF-alpha an tibody in a dose-dependent manner. The molecular weight of the factor as assessed by gel electrophoresis is 6 kd. Conclusions: Human seminal plasma contains a mitogen that is similar to TGF-alpha.