APOLIPOPROTEIN-B METABOLISM IN HYPERTRIGLYCERIDEMIC DIABETIC-PATIENTSADMINISTERED EITHER A FISH OIL-ENRICHED OR VEGETABLE OIL-ENRICHED DIET

The effect on apolipoprotein B kinetics of a diet enriched in either f ish oil or safflower oil was investigated in five hypertriglyceridemic (HTG), non-insulin-dependent diabetic subjects. The fish oil diet dec reased plasma triglycerides and VLDL-apoB but increased LDL-apoB and L DL-cholesterol. Total plasma apoB concentration did not change, nor di d the increased VLDL-apoB secretion present in these HTG subjects, whi ch, accompanied by impaired lipolysis, accounted for their elevated VL DL. The fish oil-induced fall in VLDL resulted from a decrease in secr etion without a change in residence time. The IDL fraction, which also contained small VLDL, was the primary site for the secretion of apoB particles in the HTG subjects. On the fish oil diet there was a furthe r, compensatory increase in the secretion of these lipoproteins such t hat the transport of apoB in IDL remained the same, as did its mass. I n the HTG subjects the major portion of IDL lipoproteins was cataboliz ed, with LDL-apoB production comprising the lesser quantity. On the fi sh oil diet, a shift in the channeling of the lipoprotein output from IDL resulted in a decrease in the catabolic pathway and an increase in conversion to LDL. As the residence time of LDL did not change, this increased input gave rise to the larger mass of LDL-apoB seen in these hypertriglyceridemic subjects when receiving a fish oil diet.