Effects of an antimitotic agent (cyclophosphamide) on plasma lipoproteins.

A cyclophosphamide injection to male New Zealand white rabbits induced a pronounced hypertriglyceridemia and a hypercholesterolemia whose concentration was maximal at 16 hr. Different doses were studied. In this hyperlipemia significant changes in plasma lipoprotein fractions appeared: the very low density lipoproteins increased and the high density lipoproteins decreased. Lipid composition showed that HDL cholesterol was very low comparatively to a high VLDL cholesterol. The apoprotein composition of VLDL from treated rabbits was studied and compared to that of normal rabbits. After electrophoresis in urea/polyacrylamide gels, two new apoproteins which resembled those observed in irradiated rabbits appeared. The molecular weight of these proteins was about 10,000, and they focused into three bands with isoelectric points of 6.72, 6.42 and 6.10. Total lipoprotein lipase activity in treated rabbits decreased; it was very low with 32.5 mg/kg. This lipolytic activity remains to be studied after separation of hepatic triacylglycerol lipase and lipoprotein lipase activities by chromatography.