EFFECTS OF HYPERLIPIDEMIAS IN HAMSTERS ON LIPID TRANSFER PROTEIN-ACTIVITY AND UNIDIRECTIONAL CHOLESTERYL ESTER TRANSFER IN PLASMA

Experiments were performed to characterize plasma lipid transfer protein activity (LTA), and the rate of [H-3]CE transfer from HDL to lower density lipoproteins in plasma of hamsters. Compared to rabbits, hamster plasma has about one-tenth the level of d > 1.21 LTA but a relatively high level of VLDL-triacylglycerols, and a higher fractional rate of HDL-[H-3]CE transfer in plasma (in vitro) than predicted by the d > 1.21 LTA. Like the rat, hamster plasma contains an inhibitor(s) of LTA; the level of the inhibitor activity in d > 1.21 g/ml plasma was similar in normal and hyperlipoproteinemic hamsters. Hypertriglyceridemia in sucrose-fed hamsters did not affect LTA, cholesteryl ester transfer or the plasma level of HDL-CE. However, a comparable degree of hypercholesterolemia was associated with a 122% increase in plasma d > 1.21 LTA and a 63% increase in the fractional rate of [H-3]CE transfer from HDL to lower density lipoproteins in plasma. Cholesterol feeding in hamsters was associated with increased plasma levels of LDL-cholesterol and, to a lesser extent, with VLDL- and IDL-cholesterol.