Stimulation of Testosterone Production in Isolated Rabbit Thecal Tissue by LH/FSH, Dibutyryl Cyclic AMP, PGF2α, 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 (.apprx.50,000 cells) and theca tissue (16 pieces/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 IU/ml LH/FSH [luteinizing hormone/follicle-stimulating hormone] (Pergonal), 10-3 M dibutyryl cyclic AMP (Bu2cAMP), 1 .mu.g/ml prostaglandin F2.alpha. (PGF2.alpha.), or 1 .mu.g/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, PGF2.alpha. or PGE2 did not significantly stimulate T production. After 2 days in vitro, very little T (< 200 pg/culture) was produced by control and PG-treated granulosa cells; 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 1st 2 days in culture, and the mean amount of T was stimulated 13.6 fold by LH/FSH, 3.6 fold by Bu2cAMP and 3 fold by PGF2.alpha. 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). Under the present conditions, pieces of rabbit thecal tissue probably 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, PGE2.alpha. and PGE2.