Regulation of thioredoxin mRNA in the rat uterus by gonadal steroids

Estradiol has been shown to increase the level of thioredoxin mRNA in the uterus of the ovariectomized (ovx) rat. In this study the influence of progesterone, androgens, the anti-estrogen ICI 182780 and the anti-androgen Flutamid on thioredoxin expression, has been studied in the rat uterus. Thioredoxin mRNA concentrations were determined by solution hybridization. Ovx rats treated with progesterone alone showed no effect on thioredoxin expression. Combined treatment of ICI 182780 and estradiol attenuated the estradiol-induced increase in thioredoxin mRNA. When ovx rats were treated with a testosterone depot, the amount of thioredoxin mRNA was increased five-fold after 48 h and remained at that level during the rest of the 168 h monitored. A similar increase in thioredoxin mRNA could be seen after 5-dihydrotestosterone treatment, indicating a true androgenic effect. In addition, the anti-androgen Flutamid attenuated the thioredoxin mRNA increase seen after 5-dihydrotestosterone treatment alone.

It is concluded that thioredoxin mRNA is regulated by growth promoting gonadal steroids in the rat uterus. The attenuation of the estrogen and androgen-induced increases of the thioredoxin mRNA with ICI 182780 and Flutamid, indicate that the effect is mediated via the estrogen receptor and androgen receptor respectively. None of these hormones affected the hepatic thioredoxin mRNA level in the same animals.