Stimulation of testosterone production in isolated rabbit thecal tissue by LH/FSH, dibutyryl cyclic AMP, PGE2alpha, and PGE2.

ABSTRACT

The capacities of isolated rabbit theca and granulosa cells to secrete testosterone were studied in vitro. Large Graafian follicles (1-1.5 mm in diameter) were dissected intact from the ovaries of adult estrous rabbits. Granulosa cells from 4 follicles (50,000 cells) and theca tissue (16 pieces per dish, equivalent to 4 follicles) were cultured separately for 6 days either as controls (without exogenous hormones) or with one of the following agents 1 lU/ml LH/FSH (Pergonal), 10-3M dibutyryl cyclic AMP (Bu2cAMP), 1 mug/ml prostaglandin F2alpha (PGF2alpha), or 1 mug/ml prostaglandin E2 (PGE2). The media were collected every 2 days, and the testosterone (T) was measured by radioimmunoassay. The control cultures of granulosa cells secreted small amounts of T (700 +/- 317 pg/culture mean +/-SE) during the first 2 days in vitro, and the addition of LH/FSH, Bu2cAMP, PGF2alpha, or PGE2 did not significantly stimulate T production. After 2 days in vitro, very little T (greater than 200 pg/culture) was produced by control and prostaglandin-treated granulosa cells, whereas those incubated with LH/FSH and Bu2cAMP maintained their initial T production rates. Theca control cultures produced 3 +/- 0.4 ng of T (mean +/- SE) during the first 2 days in 13.6-fold by LH/FSH, 3.6-fold by Bu2cAMP, and 3-fold by PGF2alpha and PGE2- T was not detected in theca cultures after 2 days except in those treated with LH/FSH or Bu2cAMP, which produced 1.5 +/- 0.5 and 1.6 +/- 0.3 ng of T, respectively, at 4 days (mean +/- SE). These results suggest that under the present conditions, pieces of rabbit thecal tissue have a greater capacity to produce T de novo than do isolated granulosa cells, and indicate that T production is transiently stimulated by LH/FSH, Bu2cAMP, PGE2alpha, and PGE2.