THE AMINO-ACID NITROGEN OF THE BLOOD

Abstract

Two opposing views are held concerning the manner in which the organism assimilates the amino-acids formed in the intestine from digested proteins.Abderhalden' believes that in passing the intestinal wall the amino-acids are synthesized into a blood protein.This enters the circulation, from which the cells of the tissues take it, break it down again into amino-acids and from these rebuild their own characteristic proteins.The reason for this view, that the aminoacids are resynthesized into protein while passing the intestinal wall, is, that although amino-acids are abundant in the intestinal contents, attempts to demonstrate them in normal blood have met with absolute failure.Against this view the objection is valid, that it is based on negative results and that more sensitive methods than those hitherto applied might reveal amino-acids in the blood.Buglia2 offers evidence indicating that the body is capable of utilizing amino-acids which have entered the blood stream.He injected intravenously into dogs amounts of amino-acid mixtures comparable to those formed from the food, and found that, when the injection was performed slowly, no serious ill effects followed and only a small part of the amino-acid nitrogen was excret'ed.Folin and Denis injected large amounts of amino-acids directly into the small intestines of cats and noted a subsequent increase 1