[Prolactin and specific binding of testosterone in cultured cells of the seminal vesicle of Gobius niger L].

Cultured seminal vesicle cells of Gobius niger L., precultured for about 15 days, are tested for their Testosterone-binding capacity. This whole cell system shows a specific binding of the androgen, reaching saturation in the presence of increasing amounts of ligand and the Scatchard Plot indicates a good affinity (KD = 4.4 x 10(-9) M), involving a number of sites of 5.06 x 10(-15) mole/culture. The possible existence of a second binding-site population with lower affinity and greater number of sites remains to be demonstrated. At 18 degrees C, the time course shows a maximal binding after about 60 min. of incubation, followed by a rapid decline at 90 min. The competition experiments involving estradiol, 11-keto- and 11-hydroxytestosterone indicate an effective if not total specificity to these steroids. The cross-reaction percentages at the 50% binding level are respectively 10.9, 8.5, 4.02%. Ovine Prolactin treatment of the cultures for 6 days before the binding experiment significantly improves the specific binding level of testosterone if compared to the controls (p .019, p .005). This result indicates that the Prolactin-Testosterone synergistic data already obtained on the seminal vesicles of Siluridae and Gobiidae is explained by a direct effect of the Prolactin on the androgen receptor level in the seminal vesicle cell.