Rat adipose tissue amino acid metabolism in vivo as assessed by
microdialysis and arterio-venous techniques.
Kowalski, Timothy J., Guoyao Wu, and Malcolm Watford.
Department of Nutritional Sciences, Cook College, Rutgers
University, PO Box 231 Thompson Hall New Brunswick, New Jersey
08903., Department of Animal Science and Nutrition, Texas A & M
University, College Station, Texas 77843.
APStracts 4:0121E, 1997.
In fed, anesthetized rats, microdialysis demonstrated a net release of
glycerol, glutamine, serine, tyrosine, and taurine, and a net uptake
of glutamate, aspartate, glycine and arginine, across the inguinal
adipose depot. However, the results also indicated excessive
proteolysis associated with implantation of the microdialysis probe
and a novel arteriovenous difference technique was developed.
Arteriovenous difference across the inguinal fat pat demonstrated a
net uptake of glucose, and a net release of lactate and glycerol.
Starvation (48 h) resulted in higher rates of glycerol and lactate
release with lower rates of glucose uptake. A net uptake of
triacylglycerol was seen in starved/refed animals. Net glutamine,
tyrosine and taurine release were seen in fed and starved animals,
but in starved/refed animals taurine and serine were the only amino
acids showing significant release. No significant net uptake or
release of ammonia, pyruvate or alanine was observed. These
experiments confirm that adipose tissue is a site of glutamine
synthesis and suggest that the principal substrates are derived from
intracellular proteolysis. The results also demonstrate the viability
of an arteriovenous difference technique for the study of adipose
tissue in the rat.
Received 1997 January 3; accepted in final form 1997 May 30
APS Manuscript Number E001-7.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 11 June 1997