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Pharmacological PPARalpha activation markedly alters plasma turnover of the amino acids glycine, serine and arginine in the rat

Abstract

The current study extends previously reported PPARalpha agonist WY 14,643 (30 micromol/kg/day for 4 weeks) effects on circulating amino acid concentrations in rats fed a 48% saturated fat diet. Steady-state tracer experiments were used to examine in vivo kinetic mechanisms underlying altered plasma serine, glycine and arginine levels. Urinary urea and creatinine excretion were measured to assess whole-body amino acid catabolism. WY 14,643 treated animals demonstrated reduced efficiency to convert food consumed to body weight gain while liver weight was increased compared to controls. WY 14,643 raised total amino acid concentration (38%), largely explained by glycine, serine and threonine increases. 3H-glycine, 14C-serine and 14C-arginine tracer studies revealed elevated rates of appearance (Ra) for glycine (45.5+/-5.8 versus 17.4+/-2.7 micromol/kg/min) and serine (21.0+/-1.4 versus 12.0+/-1.0) in WY 14,643 versus control. Arginine was substantially decreased (-62%) in plasma with estimated Ra reduced from 3.1+/-0.3 to 1.2+/-0.2 micromol/kg/min in control versus WY 14,643. Nitrogen excretion over 24 hours was unaltered. Hepatic arginase activity was substantially decreased by WY 14,643 treatment. In conclusion, PPARalpha agonism potently alters metabolism of several specific amino acids in the rat. The changes in circulating levels of serine, glycine and arginine reflected altered fluxes into the plasma rather than changes in clearance or catabolism. This suggests that PPARalpha has an important role in modulating serine, glycine and arginine de novo synthesis.

Type Journal
ISBN 1932-6203 (Electronic) 1932-6203 (Linking)
Authors Ericsson, A.; Turner, N.; Hansson, G. I.; Wallenius, K.; Oakes, N. D.;
Garvan Authors Dr Nigel Turner
Publisher Name PLoS ONE
Published Date 2014-01-01 00:00:00
Published Volume 9
Published Issue 12
Published Pages e113328
URL http://www.ncbi.nlm.nih.gov/pubmed/25486018
Status Published In-print
OpenAccess Link https://publications.gimr.garvan.org.au/download.php?12625_13069/2014-Ericsson-PLoS One.pdf