Lowering of plasma cholesterol in herbivores and omnivores by low molecular weight dextran

Two rabbits and two home pigs were infused in a cross-over design with equal volumes, adapted to the plasma volumes of the animals, of dextran-40 and saline. The infusions resulted in a reduction of plasma cholesterol and control parameters, such as plasma protein, hemoglobin, and hematocrit. The reduction of hemoglobin and hematocrit was related to plasma expansion with both infusion regimens. With dextran-40 infusions the reduction of plasma protein was greater than hemodilution in both species (-18% in rabbits and -20% in home pigs), because of steric exclusion of the protein. Lowering of plasma cholesterol in rabbits was comparable to the reduction in plasma protein, whereas in home pigs the reduction of plasma cholesterol (-25%) surpassed that of plasma protein. Reports in the literature have shown that dextran infusions increase cholesterol concentration in liver cells, leading to a reduction of intestinal cholesterol resorption in omnivores. This dextran effect is supposed to be responsible for the observed additional reduction of plasma cholesterol levels in omnivores.