In the present study the effects of chromium and tamoxifen given alone and in combination on female sex hormones, lipid profile and uterine contractility to oxytocin were studied in female rats in estrous stage. The drugs alone and their combinations were given orally by gavage to rats for 30 days. Results of this investigation showed that hyperlipidemic rats treated with the solvent exhibited some sort of changes in the plasma levels of female sex hormones. Hyperlipidemia per se decreased estradiol (E2) and Luteinizing hormones (LH) , while increased the FSH and cortisol blood levels. Hypercholesterolemic diet significantly increased the plasma levels of Total cholesterol (TC), Triglycerides (TG), Low-density lipoprotein cholesterol (LDL-C) and Very-low density lipoprotein cholesterol (VLDL-C). However, the diet decreased the High- density lipoprotein cholesterol (HDL-C). It dramatically decreased the oxytocin-induced uterine contractions of the isolated rat uterus in the estrous stage compared to the normolipidemic rats. Chromium decreased the E, and cortisol, while increased the progesterone and LH levels. Tamoxifen and its combination with chromium increased the E2, LH and Follicle stimulating hormone (FSH), and decreased the progesterone blood levels. Cortisol levels were reduced by the combination only but did not affected by tamoxifen alone. Chromium decreased, while its combination with tamoxifen increased the oxytocin-induced uterine contractions, compared to the hyperlipidemic control. Chromium, tamoxifen and their combination decreased the plasma levels of TC, TG, LDL-C and VLDL-C, while they increased the levels of HDL-C.
It could be concluded that, in spite of their capability to reduce the plasma levels of total cholesterol and other cholesterol containing particles, both tamoxifen and chromium exert different effects on hormonal blood levels. Chromium decreased while tamoxifen increased both estradiol and cortisol levels. Chromium increased progesterone while, tamoxifen decreased it. Tamoxifen, which decreased the levels of cholesterol, increased the hormonal blood levels and steroidogenesis, while, chromium decreased both. The effect of chromium on female sex hormones may be correlated to its cholesterol lowering capacity and its antihyperlipidemic effect, however, there is no correlation in the effects of tamoxifen. The reducing effect of chromium on the oxytocin-induced uterine contractions should be taken into consideration, especially in pregnant women, because it may decrease the uterine activity and contractions during labor.