Modulation by dexamethasone of the pyruvate dehydrogenase-complex activity in 3T3-L1 adipocytes.
Chronic exposure of 3T3-L1 pre-adipocytes to dexamethasone plus 3-isobutyl-1-methylxanthine (IBMX) with or without insulin caused a significant increase in the specific activity of 'total' pyruvate dehydrogenase complex (PDC) and in the percentage of the 'active' form of the complex compared with cells exposed to a chronic insulin treatment or an acute treatment (2 days) with dexamethasone plus IBMX. In acute-drug-switch-over experiments, dexamethasone also caused an increase in the percentage of 'active' PDC in 3T3-L1 adipocytes. The results show that, in 3T3-L1 adipocytes, dexamethasone, even in the absence of insulin, increases the proportion of PDC in its 'active' form. The mechanism of the dexamethasone effect remains to be investigated.
Patel
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MS
Raefsky
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Hu
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Ho
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D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000273:Adipose Tissue / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D003907:Dexamethasone / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology; D051379:Mice; D008815:Mice, Inbred Strains; D011768:Pyruvate Dehydrogenase Complex / Q000378:metabolism*
D007328:Insulin; D011768:Pyruvate Dehydrogenase Complex; D003907:Dexamethasone; D015056:1-Methyl-3-isobutylxanthine