Beta Estradiol Receptor Modulates Liver Lipid and Ketone Metabolism

Non-selective hormone replacement with estradiol improves metabolic homeostasis during menopause. However, this treatment is not recommended for individuals with genetic predisposition to hormone-responsive cancers. In contrast, selective activation of estrogen receptor beta (ER{beta}) has shown promising results, promoting antitumor effects and modulating metabolic outcomes, although mechanisms in which these changes occur remain poorly understood. We investigated the effects of ER{beta} activation using diarylpropionitrile (DPN), a selective ER{beta} agonist, in both an in vivo model of post menopause and in vitro models of metabolic overload. Female Wistar rats were submitted to ovariectomy (OVX) and later treated with DPN. ER{beta} agonist treatment recovered fasting glucose and lipid profiles, improved pancreatic islet morphology, and reduced retroperitoneal white adipose tissue. Serum ketone bodies and free fatty acids levels were also recovered to control levels, suggesting a modulation in liver lipid oxidation. To isolate the direct effects mechanistically, hepatocytes were submitted to nutrient overload and treated with DPN. In vitro, DPN also recovered ketone body secretion and promoted an increased dependence on complete fatty acid oxidation as well as decreased metabolic flexibility, as assessed by modulated extracellular flux analysis. Overall, these findings demonstrate a new role of ER{beta} in the modulation of hepatic lipid and ketone metabolism, with positive metabolic outcomes in estradiol-deficient animals.