Parallel changes in plasma cholesterol and lipid transfer activity in pregnant rabbits

The relationship between the concentration of plasma cholesterol and the lipid transfer activity (LTA) of lipoprotein-deficient plasma (d greater than 1.21) was studied in two models of pregnancy in the rabbit. Plasma cholesterol and the protein-mediated transfer of cholesteryl ester and triglyceride were monitored throughout gestation, 48 hr after parturition, and during lactation in New Zealand white (NZW) and heterozygous WHHL rabbits. Lipoprotein cholesterol was determined prior to and 48 hr after parturition. For both NZW and heterozygous WHHL rabbits, the progressive hypocholesterolemia of gestation was associated with parallel changes in LTA. Similarly, the rapid postpartum increase in plasma cholesterol was paralleled by increased LTA for both strains. In relation to basal values, the relative changes in plasma cholesterol and LTA were virtually identical. These data provide further evidence that in the rabbit plasma cholesterol and LTA are closely related.