Hypocholesterolemic action of the selective estrogen receptor modulator acolbifene in intact and ovariectomized rats with diet-induced hypercholesterolemia

Metabolism. 2006 May;55(5):605-13. doi: 10.1016/j.metabol.2005.11.016.

Abstract

Acolbifene (ACOL) is a fourth-generation selective estrogen receptor modulator (SERM) that has strong and pure antiestrogenic properties toward estrogen-sensitive cancers, but improves energy and lipid metabolism in an estrogen-like fashion in rodent models. The aim of this study was to determine the potency of ACOL to reduce cholesterolemia in a dietary model of hypercholesterolemia and to establish its mechanisms of action. Intact and ovariectomized (OVX) female rats were treated for 3 weeks with ACOL, and serum cholesterol and liver determinants of cholesterol metabolism were assessed. Acolbifene prevented both diet- and ovariectomy-induced weight gain and completely prevented diet-induced hypercholesterolemia. Relative to a reference chow diet, the high-cholesterol diet decreased the high-density lipoprotein (HDL) cholesterol fraction, which remained unaffected by ACOL, indicating that in hypercholesterolemic conditions, ACOL modulated only the non-HDL fraction. No impact of ACOL on determinants of liver cholesterol synthesis was observed. In contrast, ACOL increased hepatic low-density lipoprotein receptor protein in both intact and OVX rats, which was negatively correlated with serum total and non-HDL cholesterol (r=-0.59, P<.0001), suggesting a contribution of receptor-mediated hepatic uptake of cholesterol-rich lipoproteins to the hypocholesterolemic effect of ACOL. These findings establish that ACOL retains its powerful cholesterol-lowering action in diet-induced hypercholesterolemia and suggest that the SERM acts in such conditions through favoring hepatic low-density lipoprotein receptor-mediated uptake of cholesterol transported by non-HDL lipoprotein fractions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP-Binding Cassette Transporters / genetics
  • ATP-Binding Cassette Transporters / metabolism
  • Animals
  • Blood Glucose / metabolism
  • Cholesterol, Dietary / metabolism
  • Female
  • Hydroxymethylglutaryl CoA Reductases / metabolism
  • Hypercholesterolemia / drug therapy*
  • Hypercholesterolemia / metabolism
  • Liver / metabolism
  • Ovariectomy
  • Piperidines / pharmacology*
  • RNA, Messenger / chemistry
  • RNA, Messenger / genetics
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, LDL / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Selective Estrogen Receptor Modulators / pharmacology*
  • Statistics, Nonparametric
  • Sterol Regulatory Element Binding Proteins / genetics
  • Sterol Regulatory Element Binding Proteins / metabolism
  • Weight Gain

Substances

  • ATP-Binding Cassette Transporters
  • Blood Glucose
  • Cholesterol, Dietary
  • Piperidines
  • RNA, Messenger
  • Receptors, LDL
  • Selective Estrogen Receptor Modulators
  • Sterol Regulatory Element Binding Proteins
  • ritetronium
  • Hydroxymethylglutaryl CoA Reductases