ABSTRACT
Glutamine and alanine are the major amino acids released from the muscle and subsequent utilization of alanine has been proposed to occur via an alanine-glucose cycle very similar to the recycling of lactate in the Cori cycle. A major consideration in a review of the utilization of glutamine as an energy source is the methodology and systems being employed for the various studies. A comparison of the rates of utilization of various potential energy sources indicates that the intestine, fibroblasts, tumor cells, lymphocytes, brain, heart, chondrocytes, reticulocytes, eye lens, and oocytes are among tissues that are likely candidates for the utilization of glutamine as a respiratory substrate. The bioenergetics of cancer cells have been extensively studied since O. Warburg proposed that cancer cells may have an impaired respiratory capacity which is compensated by increased rate of glycolysis.
