Biochemical Studies on Livers of Chicks Receiving Graded Levels of Pteroylglutamic Acid. *

Abstract

Summary

Determinations of desoxypentose nucleic acid and pentose nucleic acid, pteroylglutamic acid (PGA), and conjugase have been made on the livers of chicks receiving 0, 5, 10, 20, 40, 80, 200, and 1000 pg of PGA per 100 g of diet and on controls receiving a commercial diet. Desoxypentose nucleic acid was found to be somewhat low in the livers of the negative control group of chicks but differences between all other groups uere of doubtful significance.

The liver conjugase levels of the various groups, whether determined at pH 4.5 or at pH 7.0, were found to be unrelated to the dietary intake of PGA and to the nucleic acid content of the livers.

The liver PGA freed by autolysis was approximately the same as that determinable after treatment with either chick pancreas conjugase or hog kidney conjugase. The levels of PGA found in the chick livers indicate that storage of excess vitamin did not take place until the dietary level exceeded 40 μg per 100 g.

The bearing that the findings have on the mode of action of dietary PGA in reducing liver xanthine oxidase is briefly discussed.