Sex differences in hepatic regulation of cholesterol homeostasis

Physiological sex-differences may influence metabolic status and then alter the onset of some diseases. According to recent studies it is now well established that females are more protected from hypercholesterolemia-related diseases, such as cardiovascular diseases until menopause. Female protection from hypercholesterolemia is mediated by the hypolipidemic properties of estrogens, even if mechanisms underlying this protection remain still debated. Even though the regulatory mechanisms of cholesterol homeostasis maintenance are well known, few data are available on the supposed differences between male and female in these processes. So, the aim of this work was to define, through an in vivo study, the putative sex-dependent regulation of the processes underlying cholesterol homeostasis maintenance. We examined 3-hydroxy 3-methylglutaryl coenzyme A reductase and its regulatory protein network as well as the amount of low density lipoprotein receptor and cholesterol. The study was conducted in the liver and plasma of male and female rats, on adults and during postnatal development, and on 17--estradiol-treated male rats. Our data support that physiological differences in proteins involved in cholesterol balance are present between the sexes, and in particular, 3-hydroxy 3-methylglutaryl coenzyme A reductase show