When solutions of sugar-forming amino acids are given parenterally or orally to phlorhizinized dogs, extra sugar and nitrogen are excreted in the urine.
The route of administration does not influence the way in which the amino acids are metabolized. 89 percent of the expected sugar was recovered when the acids were fed and 81 per cent when the acids were administered parenterally.
Casein digests are metabolized like the amino acids with extra sugar and nitrogen excreted in the urine.
When casein digest is given orally there is an average conversion into sugar of 53 per cent, as compared with 56 per cent intravenously.
Solutions of amino acids or casein digests are readily available sources to the body of nitrogen and carbohydrate.