Altered plasma concentrations of sex hormones in cats infected by feline immunodeficiency virus or feline leukemia virus.

Gender differences may affect human immunodeficiency virus (HIV) infection in humans and may be related to fluctuations in sex hormone concentration. The different percentage of male and female cats observed to be infected by feline leukemia virus (FeLV) or feline immunodeficiency virus (FIV) has been traditionally explained through the transmission mechanisms of both viruses. However, sexual hormones may also play a role in this different distribution. To study this possibility, 17ß-estradiol, progesterone, testosterone, and dehydroepiandrosterone (DHEA) concentrations were analyzed using a competitive enzyme immunoassay in the plasma of 258 cats naturally infected by FIV (FIV(+)), FeLV (FeLV(+)), or FeLV and FIV (F(-)F(+)) or negative for both viruses, including both sick and clinically healthy animals. Results indicated that the concentrations of 17ß-estradiol and testosterone were significantly higher in animals infected with FIV or FeLV (P < 0.05) than in negative cats. Plasma concentrations of DHEA in cats infected by either retrovirus were lower than in negative animals (P < 0.05), and F(-)F(+) cats had significantly lower plasma values than monoinfected cats (P < 0.05). No significant differences were detected in the plasma concentration of progesterone of the four groups. No relevant differences were detected in the hormone concentrations between animal genders, except that FIV(+) females had higher DHEA concentrations than the corresponding males (P < 0.05). In addition, no differences were observed in the hormone concentrations between retrovirus-infected and noninfected animals with and without clinical signs. These results suggest that FIV and FeLV infections are associated with an important deregulation of steroids, possibly from early in the infection process, which might have decisive consequences for disease progression.

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 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)

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