Lack of effect on the low density lipoprotein receptor in hamsters treated with 17 alpha-ethinyl estradiol

High pharmacological doses of 17 alpha-ethinyl estradiol are known to increase the number of low density lipoproteins (LDL)-receptors in rats and rabbits, leading to a profound decrease in plasma cholesterol levels. Here, using rats as a positive control, we demonstrate that in hamsters ethinyl estradiol does not upregulate liver LDL-receptors, nor change plasma LDL turnover or plasma LDL-cholesterol. The lack of effect in estradiol-treated hamsters suggests that the hormonal control is different from that in rats.