Glycogen Formation from Amino Acids.

Abstract

One lot of control rats was kept on stock diet until killed in order to establish the glycogen and lipid contents of the liver without a starvation period. A second lot of control rats was starved for 24 hours before killing, from which group the fasting level was derived.

The remaining rats were starved 18 hours, then fed the amino acid to be investigated, and killed 6 hours later. Forced feeding was resorted to, except in the case of tyrosine. This amino acid, suspended in water, was applied to the rats'hair about the head and neck region. The animals cleaned it off nicely, thereby getting practically all of it into the gastro-intestinal tract. The other amino acids used did not lend themselves readily to this method of feeding, in which studies, feeding was performed by means of a medicine dropper. The disadvantage of the latter method lies in the rather large amount of water which must be introduced in keeping the amino acid conveniently suspended. The amount of amino acid fed in each case was approximately 2 gm.

The amino acids were purchased from the Eastman Kodak Company. They were d-1 alanine, 1-cystine, d-glutamic acid (practical), glycine, and 1-tyrosine.

The results are presented in Table I. The mean body weight, liver weight, liver weight expressed as % of body weight, % of liver glycogen, and % of liver lipid are tabulated. In each case the results for the males are shown first, those for the females second, and those for the sexes combined, finally. The number of each sex studied is indicated in the first column. Lipid determinations were not made in every case.

Owing to the small number of cases, the statistical method of analysis proved impractical.