Testosterone directly induces progesterone production and interacts with physiological concentrations of LH to increase granulosa cell progesterone production in laying hens (Gallus domesticus)

Blocking testosterone action with immunization or with a specific antagonist blocks the preovulatory surge of progesterone and ovulation in laying hens. Thus, testosterone may stimulate progesterone production in a paracrine fashion within the ovary. To test this hypothesis, we evaluated the effects of testosterone and its interaction with LH on the production of progesterone by granulosa cells in culture. Hen granulosa cells obtained from preovulatory follicles were cultured in 96 well plates. The effects of testosterone (0-100 ng/ml) and/or LH (0-100 ng/ml) were evaluated. LH-stimulated progesterone production in a dose response manner up to 10 ng/ml (p < 0.01). Testosterone, up to 10 ng/ml, increased progesterone production in a dose response manner in the absence of LH and at all doses of LH up to I ng/ml (p < 0.001). However, at supraphysiological concentrations of LH (10 and 100 ng/ml) there was no further increase in progesterone production caused by testosterone (p > 0.05). Finally, the addition of 2-hydroxyflutamide (0-1000 mu g/ml) to hen granulosa cells cultured with 10 ng/ml of testosterone reduced progesterone production in a dose response manner (p < 0.001). In conclusion, testosterone stimulates progesterone production in preovulatory follicle granulosa cells and interacts with physiological concentrations of LH to increase progesterone production. In addition, testosterone stimulation on granulosa cells is specific since the testosterone antagonist decreased testosterone stimulatory action. (c) 2006 Elsevier B.V. All rights reserved.