Endothelial Fibrinolytic Activity in Hypercholesterolemic and Diabetic Rats; Effect of Stanozolol, Streptozotocin, Dexamethasone and Hypophysectomy

Abstract

In genetically hypercholesterolaemic rats (RICO) the intimal plasminogen activator activity (PAA) at the nonbranching regions of the aorta, but not at the branching regions, was markedly lower than in controls. In alloxan-induced diabetes in rats, the pattern of changes in tissue PAA was different in different tissues. The anabolic steroid stanozolol induced in male rats a dose and time dependent increase in the tissue PAA; this increase was varying from one tissue to another. The antibiotic streptozotocin, at a diabetogenic dose, induced a 200% increase in the intimal PAA of the aorta in RICO rats and by 100% in controls ( normal rats) ten weeks after a single injection. Administration of dexamethasone in normal rates 24 hours and 3 hours before streptozotocin injection prevented the enhancement of PAA. However, administration of dexamethasone simultaneously with streptozotocin did not affect the enhancement of the intimal PAA. The hypophysectomy induced in rats significantly increased PAA in the intima of the aorta.