Abstract
The nonmetabolizable amino acids .alpha.-aminoisobutyric acid (AIB) and cycloleucine and the poorly metabolizable amino acid D-alanine potently stimulated hepatic ornithine decarboxylase (ODC) activity in starved rats. The stimulation by AIB had several of the characteristics of stimulation by a protein meal and occurred in hypophysectomized animals. AIB also stimulated renal, but not brain or heart, ODC activity.