The effect of dexamethasone on disruption of ovarian steroid levels and receptors in female rats.

This study was conducted to investigate if the injection of a single dose of dexamethasone may cause disruption of adult female rat gonadal function in terms of plasma and ovarian level of both androgen and estrogen, ovarian morphology, and changes in localization of androgen, estrogen and glucocorticoid receptors. Adult female Long Evans rats (n=50, 250-300 g) were used. At day 0 rats received subcutaneously 1 ml of saline (n=25; control group) or dexamethasone at 0.1 mg/kg (n=25, treated group). Rats were sacrificed in groups of five on days 10, 15, 20, 25 and 30 after injection. Blood samples and one ovary were collected to analyze dexamethasone, 17beta-estradiol (E2), testosterone (T) and androstenedione (A4) concentrations by amplified EIA. The remaining ovary was removed and processed for histopathology and immunocytochemistry. Differences between individual means were analyzed by Pairwise t-test and Bonferroni post test to asses whether values presented statistical significance. Increased E2, T and A4 levels were observed both in plasma and ovary samples in treated group when comparing with control (p< 0.01) at all days post-injection even when dexamethasone was undetectable. Ovarian morphology of treated group showed features compatible with female infertility. Inmmunolocalization of androgen and estrogen receptors showed that both were negative in treated group while controls showed highest positivity (AR +++, ER ++). Glucocorticoid receptor showed higher positivity in dexamethasone treated rats (GR ++) than in controls (GR +). Obtained results showed clear evidence that a single dose of dexamethasone may disrupt gonadal function in rats, and that possibly leads to infertility.