In:
American Journal of Physiology-Endocrinology and Metabolism, American Physiological Society, Vol. 293, No. 5 ( 2007-11), p. E1352-E1357
Abstract:
The pathways of glycerol-3-phosphate (G3P) generation for glyceride synthesis were examined in precision-cut liver slices of fasted and diabetic rats. The incorporation of 5 mM [U- 14 C]glucose into glyceride-glycerol, used to evaluate G3P generation via glycolysis, was reduced by ∼26–36% in liver slices of fasted and diabetic rats. The glycolytic flux was reduced by ∼60% in both groups. The incorporation of 1.0 mM [2- 14 C]pyruvate into glyceride-glycerol (glyceroneogenesis) increased ∼50% and ∼36% in slices of fasted and diabetic rats, respectively, which also showed a two-fold increase in the activity phospho enolpyruvate carboxykinase. The increased incorporation of 1.0 mM [2- 14 C]pyruvate into glyceride-glycerol by slices of fasted rats was not affected by the addition of 5 mM glucose to the incubation medium. The activity of glycerokinase and the incorporation of 1 mM [U- 14 C]glycerol into glyceride-glycerol, evaluators of G3P formation by direct glycerol phosphorylation, did not differ significantly from controls in slices of the two experimental groups. Rates of incorporation of 1 mM [2- 14 C]pyruvate and [U- 14 C]glycerol into glucose of incubation medium (gluconeogenesis) were ∼140 and ∼20% higher in fasted and diabetic slices than in control slices. It could be estimated that glyceroneogenesis by liver slices of fasted rats contributed with ∼20% of G3P generated for glyceride-glycerol synthesis, the glycolytic pathway with ∼5%, and direct phosphorylation of glycerol by glycerokinase with ∼75%. Pyruvate contributed with 54% and glycerol with 46% of gluconeogenesis. The present data indicate that glyceroneogenesis has a significant participation in the generation of G3P needed for the increased glyceride-glycerol synthesis in liver during fasting and diabetes.
Type of Medium:
Online Resource
ISSN:
0193-1849
,
1522-1555
DOI:
10.1152/ajpendo.00394.2007
Language:
English
Publisher:
American Physiological Society
Publication Date:
2007
detail.hit.zdb_id:
1477331-4
SSG:
12
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