Inhibition of cholesterol synthesis causes both hypercholesterolemia and hypocholesterolemia in hamsters.
Effects of FR194738 ((E)-N-ethyl-N-(6,6-dimethyl-2-hepten-4-ynyl)-3-[2-methyl-2-(3-thienylmethoxy)propyloxy]benzylamine hydrochloride), a squalene epoxidase inhibitor, on lipid metabolism were compared with those of pravastatin, a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, in hamsters. Drugs were given for 10 d either as a diet mixture or as a bolus oral gavage, and similar results were obtained with each type of administration. FR194738 (0.01-0.32% as a diet mixture; 10-100 mg/kg as an oral gavage) dose-dependently decreased serum total cholesterol, non high density lipoprotein (HDL) cholesterol, HDL cholesterol and triglyceride levels, and the changes in serum parameters were similar. Pravastatin (0.01-0.32% as a diet mixture; 1-100 mg/kg as an oral gavage) increased serum cholesterol levels, and dose-dependently decreased serum triglyceride levels. Although oral gavage of FR194738 at 32 mg/kg and pravastatin at 3.2 and 10 mg/kg increased hepatic HMG-CoA reductase activity, the degree of the changes was far greater with the latter than the former drug. FR194738 slightly increased hepatic cholesterol content at 32 mg/kg, whereas pravastatin dose-dependently increased hepatic cholesterol content until it leveled off at 32 and 100 mg/kg. It is concluded that inhibition of squalene epoxidase and HMG-CoA reductase triggers both hypercholesterolemic (hepatic cholesterol synthesis) and hypocholesterolemic (hepatic cholesterol uptake) mechanisms. FR194738 appears to induce a greater enhancement of the latter rather than the former, whereas pravastatin has a greater effect on the former.
Sawada
Masae
M
Department of Metabolic Diseases, Medicinal Biology Research Laboratories, Fujisawa Pharmaceutical Co, Ltd, Osaka, Japan. masae_sawada@po.fujisawa.co.jp
Matsuo
Masahiko
M
Seki
Jiro
J
D000818:Animals; D000924:Anticholesteremic Agents / Q000494:pharmacology*; D001596:Benzylamines / Q000494:pharmacology; D008076:Cholesterol, HDL / Q000096:biosynthesis* / Q000097:blood; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D050171:Dyslipidemias / Q000097:blood* / Q000201:enzymology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008297:Male; D008647:Mesocricetus; D017035:Pravastatin / Q000494:pharmacology
D000924:Anticholesteremic Agents; D001596:Benzylamines; D008076:Cholesterol, HDL; D004791:Enzyme Inhibitors; C443179:FR 194738; D017035:Pravastatin