Gastrointestinal absorption as well as gall bladder accumula tion are prime factors in determining the efficacy of oral cholecystographic agents. In this connection, the biological properties of a-aminoisobutyric acid (AIB; 2-methylalanine), are of particular interest. AIB is a nonmetabolizable amino acid,'which undergoes active intestinal transport against a concentration gradient'and accumulates in the liver. 3 Since the presence of iodine atoms ...
