| Popis: |
Certain effects of aging, reproductive status and lipid–lowering drugs on lipid metabolism, liver structure and hepatic drug metabolizing enzymes in male Sprague-Dawley, Holtzman strain rats are presented. Attention is focused on the following: 1) retired breeder rats have statistically higher serum cholesterol levels and a shorter life expectancy than age-matched virgin counterparts; 2) the retired breeder rat may be a suitable animal model for testing lipid-lowering agents and the pathogenesis of certain types of hyperlipoproteinemia; 3) oxandrolone may be an unusually potent hypocholesterolemic agent capable of inducing the proliferation of hepatic smooth endoplasmic reticulum without an associated increase in drug-metabolizing enzymes; 4) specific alterations in hepatic fine structure occur as a function of age; 5) certain age-related structural changes in the liver may be reversible; and, 6) subtle changes in cell fine structure may be detected by quantitative electron microscopy. |
