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

ABSTRACT

This study was conducted to investigate if the injection of a single dose of dexamethasonemay cause disruption of adult female rat gonadal function in terms ofplasma and ovarian level of both androgen and estrogen, ovarian morphology, andchanges in localization of androgen, estrogen and glucocorticoid receptors. Adultfemale Long Evans rats (n=50, 250-300 g) were used. At day 0 rats received subcutaneously1 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 30after injection. Blood samples and one ovary were collected to analyze dexamethasone,17â-estradiol (E2), testosterone (T) and androstenedione (A4) concentrationsby amplified EIA. The remaining ovary was removed and processed for histopathologyand immunocytochemistry. Differences between individual means were analyzedby Pairwise t-test and Bonferroni post test to asses whether values presentedstatistical significance. Increased E2, T and A4 levels were observed both in plasmaand ovary samples in treated group when comparing with control (p< 0.01) at alldays post-injection even when dexamethasone was undetectable. Ovarian morphologyof treated group showed features compatible with female infertility. Inmmunolocalizationof androgen and estrogen receptors showed that both were negativein 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 singledose of dexamethasone may disrupt gonadal function in rats, and that possiblyleads to infertility (AU)

RESUMEN

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