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Insulin stimulation of glutamine: fructose-6-phosphate amidotransferase occurs via an insulin-like growth factor-1 pathway in rat fibroblasts.

Authors: Simmons, ST  Daniels, MC  Huddleston, E  Hebert LF, JR  McClain, DA  Crook, ED 
Citation: Simmons ST, etal., Res Commun Mol Pathol Pharmacol. 1999;104(1):63-72.
Pubmed: (View Article at PubMed) PMID:10604279

The biosynthetic pathway for hexosamine mediates some of the adverse effects of high glucose. The rate limiting enzyme in this pathway is glutamine:fructose-6-phosphate amidotransferase (GFA). Using HPLC, the regulation of GFA activity by glucose and insulin was studied in wild type and rat-1 fibroblasts overexpressing human insulin receptors (HIRcB cells). In wild type cells only maximal doses of insulin (580 ng/ml) resulted in an increase in GFA activity (51.0 +/- 40.6%). In HIRcB cells insulin led to a dose dependent increase in GFA activity that was enhanced when compared to wild type (89 +/- 5% (p<0.001) increase at 580 ng/ml). Insulin's action was glucose dependent and required prolonged serum deprivation. HIRcB's cultured in 0 mM glucose had a 58.2% (p<0.001) decrease in insulin stimulation. However, when present the concentration of glucose (2-20 mM) did not affect insulin stimulation of GFA activity. Most of insulin's effects occur by way of the IGF-1 receptor as a two-fold stimulation of GFA activity was seen with significantly lower doses (10 ng/ml) of IGF-1. We conclude that GFA enzyme activity is upregulated by insulin and this may occur via a IGF-1 receptor mediated pathway.


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CRRD Object Information
CRRD ID: 1625427
Created: 2007-06-08
Species: All species
Last Modified: 2007-06-08
Status: ACTIVE


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