Effect of pyridoxine deficiency on cholesterogenesis in rats fed different levels of protein.

Hepatic cholesterol contents in rats fed a 70% or 20% casein diet with or without pyridoxine was determined. In the case of the 70% casein group, pyridoxine-deficient rats showed a higher content than the control. The increment was mainly due to the accumulation of an ester form of the cholesterol. On the other hand, pyridoxine-deficient rats in the 20% casein group showed a slightly lower content. The cholesterol content in liver microsomal fractions was lower in the 20% casein pyridoxine-deficient group and serum cholesterol level was lower in the 70%-casein pyridoxine-deficient group than those in respective control groups. Incorporation of [14C]acetate into cholesterol was studied using liver slices, and significant stimulation was observed in pyridoxine-deficient rat fed a 20% or 70% casein diet. There was no difference in intestinal cholesterogenesis between the control and the deficient groups.