Epidermal growth factor (EGF) in seminal plasma and prostatic gland: a radioreceptor assay

The binding ability of five different cells in culture to mouse epidermal growth factor (mEGF) was studied. A simple radioreceptor assay (RRA) using normal rat kidney cell (NRK-52E) as a source of EGF receptor was established. Maximal binding capacity and apparent dissociation constant of NRK-52E cell were 3.36 femtomoles of mEGF bound per 10(6) cells and 2.85 x 10(-11) M, respectively. EGF-like activity (EGF-LA) in seminal plasma and in cytosols of prostatic gland and seminal vesicle was 39.6 +/- 9.9 ng/ml, 0.67 +/- 0.10 ng/mg protein (mean +/- SE) and less than 0.2 ng/mg protein, respectively. The EGF-LA in seminal plasma was considered to be derived mainly from prostatic gland because the EGF-LA in cytosol of prostatic gland was higher than that of seminal vesicle.