PRODUCTION OF GLUTAMINE AND UTILIZATION OF GLUTAMATE BY RAT SUBCUTANEOUS ADIPOSE-TISSUE IN-VIVO

Production of glutamine and utilization of glutamate by rat subcutaneo us adipose tissue in vivo. Am. J. Physiol. 266 (Endocrinol. Metab. 29) : E151-E154, 1994.-Information about adipose tissue amino acid metabol ism is limited, with most data derived from studies in vitro. The purp ose of this study was to further characterize the role of adipose tiss ue in glutamine metabolism in the rat in vivo. The extracellular conce ntrations of glutamine, glutamate, alanine, and ammonia were measured in the rat inguinal fat pad using a microdialysis sampling technique. A calibration method was used to accurately assess the extracellular l evels of metabolites, and a comparison of these concentrations with th ose in arterial blood allowed determination of the net Aux of each com pound. The adipose tissue-arterial blood concentration differences wer e 122+/-19, 54+/-37, -61+/-21, and -28+/-13 mu M for glutamine, alanin e, glutamate, and ammonia, respectively, indicating a production of gl utamine and an uptake of glutamate by subcutaneous adipose tissue. The magnitude of glutamine production suggests that adipose tissue may pl ay a significant role in whole body glutamine homeostasis.