Effects of LY295427, a low-density lipoprotein (LDL) receptor up-regulator, on LDL receptor gene transcription and cholesterol metabolism in normal and hypercholesterolemic hamsters

J Pharmacol Exp Ther. 1999 Apr;289(1):85-92.

Abstract

The action of LY295427 [(3alpha,4alpha, 5alpha)-4-(2-propenylcholestan-3-ol)], a compound that derepresses low-density lipoprotein receptor (LDL-R) expression in a cell-based model, was examined in hamsters. It was found that the compound does not have an effect in normal chow-fed hamsters, in which LDL-R levels are not repressed, but exerts a marked hypocholesterolemic effect (>70% decrease) in cholesterol-coconut oil-fed hamsters, in which LDL-R is repressed. In this model, there is a dose-response for cholesterol lowering with an approximate ED50 value of 40 mg/kg/day and an inverse relationship between serum cholesterol and serum LY295427 levels. LDL-R mRNA is increased (2-fold) and liver cholesterol ester content is decreased (>90%). Unlike the 3-hydroxy-3-methylglutarylcoenzyme A reductase inhibitor lovastatin, the decreased serum cholesterol is confined to the non-high-density lipoprotein fraction. Furthermore, LY295427 does not affect cholesterol biosynthesis, and it does not have a significant effect on cholesterol absorption. These data suggest that LY295427 acts in the hypercholesterolemic hamster by derepressing LDL-R transcription, thereby enhancing cholesterol clearance from the blood. The results with LY295427 suggest that compounds that act to increase LDL-R may represent a novel approach in the pharmacotherapy for hypercholesterolemia.

MeSH terms

  • Acetates / metabolism
  • Animals
  • Anticholesteremic Agents / pharmacology*
  • Cholestanols / pharmacology*
  • Cholesterol / blood
  • Cholesterol / metabolism*
  • Cholesterol, Dietary / administration & dosage
  • Cholesterol, LDL / blood
  • Coconut Oil
  • Cocos / chemistry
  • Cricetinae
  • Dietary Fats / administration & dosage
  • Homeostasis / drug effects
  • Hypercholesterolemia / metabolism*
  • Intestinal Absorption / drug effects
  • Liver / drug effects
  • Liver / metabolism
  • Lovastatin / pharmacology
  • Male
  • Mesocricetus
  • Plant Oils / administration & dosage
  • RNA, Messenger / biosynthesis
  • Receptors, LDL / biosynthesis
  • Receptors, LDL / genetics*
  • Up-Regulation / drug effects*

Substances

  • Acetates
  • Anticholesteremic Agents
  • Cholestanols
  • Cholesterol, Dietary
  • Cholesterol, LDL
  • Dietary Fats
  • LY 295427
  • Plant Oils
  • RNA, Messenger
  • Receptors, LDL
  • Cholesterol
  • Lovastatin
  • Coconut Oil