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L ‐glutamine and palmitate catabolism in pancreatic islets from rats depleted in long‐chain polyunsaturated ω3 fatty acids
Author(s) -
Zhang Ying,
Louchami Karim,
Carpentier Yvon A.,
Malaisse Willy J.,
Sener Abdullah
Publication year - 2008
Publication title -
cell biochemistry and function
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 61
eISSN - 1099-0844
pISSN - 0263-6484
DOI - 10.1002/cbf.1403
Subject(s) - glutamine , catabolism , medicine , metabolism , endocrinology , polyunsaturated fatty acid , chemistry , endogeny , islet , azaserine , pancreatic islets , carbohydrate metabolism , biochemistry , hexose , biology , fatty acid , insulin , amino acid , enzyme
Abstract The catabolism of D ‐glucose was recently found to be impaired in pancreatic islets from rats depleted in long‐chain polyunsaturated ω3 fatty acids. The specificity of this alteration was now investigated by characterizing the oxidative fate of endogenous nutrients in islets preincubated with either L ‐[U‐ 14 C]glutamine or [U‐ 14 C]palmitate and then incubated variously in the absence of D ‐glucose, presence of the hexose or presence of metabolic poisons. Relative to their radioactive content after preincubation, the production of 14 CO 2 by islets prelabelled with [U‐ 14 C]glutamine was higher in ω3‐depleted rats than control animals. The enhancing action of D ‐glucose upon such production was impaired, however, in the ω3‐depleted rats. The net uptake of 14 C‐palmitate and absolute value for 14 CO 2 output were both increased in ω3‐depleted rats, whilst the ratio between 14 CO 2 output and islet radioactive content was decreased in the same animals. The inhibition of 14 CO 2 production by metabolic poisons was comparable in all cases. These results are consistent with recent findings on such items as the availability of endogenous amino acids and uptake of unesterified fatty acids in extrapancreatic sites of the ω3‐depleted rats. They also support the view that the alteration of D ‐glucose metabolism in the islets of the latter animals may be attributable, in part at least, to alteration of glucokinase kinetics by high intracellular acyl‐CoA levels. Copyright © 2007 John Wiley & Sons, Ltd.