title: Estrogen signaling prevents diet-induced hepatic insulin resistance in male mice with obesity.
abstract: The development of insulin resistance in the liver is a key event that drives dyslipidemia and predicts diabetes and cardiovascular risk with obesity. Clinical data show that estrogen signaling in males helps prevent adiposity and insulin resistance, which may be mediated through estrogen receptor-α (ERα). The tissues and pathways that mediate the benefits of estrogen signaling in males with obesity are not well defined. In female mice, ERα signaling in the liver helps to correct pathway-selective insulin resistance with estrogen treatment after ovariectomy. We assessed the importance of liver estrogen signaling in males using liver ERα-knockout (LKO) mice fed a high-fat diet (HFD). We found that the LKO male mice had decreased insulin sensitivity compared with their wild-type floxed (fl/fl) littermates during hyperinsulinemic euglycemic clamps. Insulin failed to suppress endogenous glucose production in LKO mice, indicating liver insulin resistance. Insulin promoted glucose disappearance in LKO and fl/fl mice similarly. In the liver, insulin failed to induce phosphorylation of Akt-Ser(473) and exclude FOXO1 from the nucleus in LKO mice, a pathway important for liver glucose and lipid metabolism. Liver triglycerides and diacylglycerides were also increased in LKO mice, which corresponded with dysregulation of insulin-stimulated ACC phosphorylation and DGAT1/2 protein levels. Our studies demonstrate that estrogen signaling through ERα in the liver helps prevent whole body and hepatic insulin resistance associated with HFD feeding in males. Augmenting hepatic estrogen signaling through ERα may lessen the impact of obesity on diabetes and cardiovascular risk in males.
authors.affiliation: Division of Diabetes, Endocrinology, and Metabolism, Department of Internal Medicine, and.
authors.forename: Lin
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee.
authors.forename: Melissa N
authors.initials: MN
authors.lastname: Martinez
authors.affiliation: Tennessee Valley Healthcare System, Division of Diabetes, Endocrinology, and Metabolism, Department of Internal Medicine, and.
authors.forename: Christopher H
authors.initials: CH
authors.lastname: Emfinger
authors.affiliation: Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee.
authors.forename: Brian T
authors.initials: BT
authors.lastname: Palmisano
authors.affiliation: Tennessee Valley Healthcare System, Division of Diabetes, Endocrinology, and Metabolism, Department of Internal Medicine, and Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee john.stafford@vanderbilt.edu.
authors.forename: John M
authors.initials: JM
authors.lastname: Stafford
mesh_terms: D000818:Animals; D051048:Diacylglycerol O-Acyltransferase / Q000378:metabolism; D059305:Diet, High-Fat / Q000009:adverse effects*; D047628:Estrogen Receptor alpha / Q000502:physiology*; D004967:Estrogens / Q000502:physiology*; D005260:Female; D007333:Insulin Resistance; D008099:Liver / Q000378:metabolism*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009765:Obesity / Q000235:genetics / Q000378:metabolism*; D012737:Sex Factors; D015398:Signal Transduction / Q000502:physiology
chemical_list: D047628:Estrogen Receptor alpha; D004967:Estrogens; C516957:DGAT2 protein, mouse; C494882:Dgat1 protein, mouse; D051048:Diacylglycerol O-Acyltransferase
keywords: and hyperinsulinemic euglycemic clamp; estrogen; estrogen receptor-α; insulin resistance; liver lipid metabolism; males; sex differences