| Abstract: | The maturation of Sertoli cell function was studied by observing properties of cells obtained from 15-, 25-, and 35-day-old rats after 3 days in culture gamma-Glutamyl transpeptidase activity, expressed per mg DNA or per mg protein, and total and soluble protein to DNA ratios increased with age. In contrast, lactate dehydrogenase activity was unchanged between 15 and 35 days of age. Secreted protein to DNA ratios and the secretion of lactate, androgen-binding protein (ABP), and transferrin per mg DNA also increased with age. Two-dimensional electrophoresis maps of [35S]methionine-labeled secretory proteins indicated the appearance of two specific bands [mol wt, 66,000; pI 6.0-6.8 (band 1); mol wt, 56,000; pI 5.3-6.0 (band 2)] between 15 and 35 days of age. The hormone dependence of these parameters was studied in Sertoli cells isolated from rats hypophysectomized at 20 days of age and subsequently treated with oil, testosterone propionate, or testosterone propionate plus FSH for 15-21 days. Hypophysectomy decreased total, soluble, and secreted protein to DNA ratios; hormone treatment in vivo increased these ratios compared to oil treatment. gamma-Glutamyl transpeptidase activity was significantly decreased by hypophysectomy and increased, compared to oil treatment, by hormone treatment. In contrast, lactate dehydrogenase activity per mg DNA was also decreased by hypophysectomy, but was unaffected by hormone treatment. [35S]Methionine incorporation into secreted protein and secretion of ABP and lactate per mg DNA were all decreased by hypophysectomy, whereas transferrin secretion per mg DNA was unaffected. While the hormone treatments increased ABP secretion, they had no effect on lactate or transferrin secretion, expressed per mg DNA. The [35S]methionine-labeled secretory proteins (bands 1 and 2) were not visible in two-dimensional electrophoresis maps after hypophysectomy of the donor animals. Treatment with testosterone propionate or testosterone propionate plus FSH in vivo resulted in the appearance of the acidic components of band 2. These data demonstrate that changes reflecting in vivo maturational patterns and hormonal influences on Sertoli cell function persist, at least in a relative sense, after 3 days in culture. Although the majority of [35S]methionine-labeled Sertoli cell cellular and secretory proteins were present under all conditions, maturation- and hormone-dependent changes in a number of specific functions were demonstrated. |
