Dogs fed a diet containing butter, cholesterol, and thiouracil develop severe hypercholesterolemia. Both a p and 8-lipoprotein cholesterol and phospholipid increase whereas these lipids in the a, fraction appear to decrease. Comparison of the dextran sulfate-precipitable lipoproteins with lipoprotein fractions obtained by ultracentrifugation a t densities 1.019, 1.063, and 1.21 and with paper e...