CHANGES IN APOPROTEIN DISTRIBUTION BETWEEN LIPOPROTEIN CLASSES OF HYPERCHOLESTEROLEMIC RATS TREATED WITH ASCORBATE

It is known that ascorbate has a lipid lowering effect, accompanied by a drop of apo B, in rats fed a diet enriched with 1.5% of cholesterol (Nath diet). In order to better clarify the role exerted by ascorbate in lipid metabolism, the effect of ascorbate administration on apolip oprotein pattern in rats fed the Nath diet was investigated, Wistar ma le rats fed for two months the Nath diet were treated i.p. with 60 mg/ kg of body weight of ascorbate for 10 days. Blood collection before an d after the treatment was performed by intracardiac puncture. Lipoprot eins were prepared by preparative ultracentrifugation and their apopro tein content was obtained by densitometric scanning of the apoprotein electhrophoretic pattern. The decrease of total plasma cholesterol and triglycerides and of cholesterol, triglycerides and protein content o f all plasma lipoproteins observed in ascorbate treated rats, is accom panied by a marked modification of the apolipoprotein pattern of all l ipoprotein classes studied, with an increase of apo E content in VLDL- IDL and LDL fractions (135 and 44% respectively), and a decrease of C (37%), AI (70%) and B (37.5%) apoproteins in VLDG-IDL and of apo C (36 %) in LDL. On the contrary, in HDL fraction ascorbate induces an incre ase of C apoproteins (26%) and a decrease of E and B apoproteins (47% and 71% respectively). The data reported clearly show that in hypercho lesterolemic rats the lipid towering effect of ascorbate administratio n, is accompanied by a marked modification of the apoprotein pattern o f all lipoprotein classes studied.