Kinetics of dexamethasone-induced alterations of glucose metabolism in healthy humans.
Six healthy human subjects were studied during three 75-g oral, [13C]glucose tolerance tests to assess the kinetics of dexamethasone-induced impairment of glucose tolerance. On one occasion, they received dexamethasone (4 x 0.5 mg/day) during the previous 2 days. On another occasion, they received a single dose (0. 5 mg) of dexamethasone 150 min before ingestion of the glucose load. On the third occasion, they received a placebo. Postload plasma glucose was significantly increased after both 2 days dexamethasone and single dose dexamethasone compared with control (P < 0.05). This corresponded to a 20-23% decrease in the metabolic clearance rate of glucose, whereas total glucose turnover ([6,6-2H]glucose), total (indirect calorimetry) and exogenous glucose oxidation (13CO2 production), and suppression of endogenous glucose production were unaffected by dexamethasone. Plasma insulin concentrations were increased after 2 days of dexamethasone but not after a single dose of dexamethasone. In a second set of experiments, the effect of a single dose of dexamethasone on insulin sensitivity was assessed in six healthy humans during a 2-h euglycemic hyperinsulinemic clamp. Dexamethasone did not significantly alter insulin sensitivity. It is concluded that acute administration of dexamethasone impairs oral glucose tolerance without significantly decreasing insulin sensitivity.
Schneiter
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P
Faculty of Medicine, Institute of Physiology, University of Lausanne, 1005 Lausanne, Switzerland.
Tappy
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L
D000328:Adult; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism*; D002245:Carbon Dioxide / Q000032:analysis; D002247:Carbon Isotopes; D003907:Dexamethasone / Q000494:pharmacology*; D005260:Female; D005947:Glucose / Q000378:metabolism*; D015309:Glucose Clamp Technique; D005951:Glucose Tolerance Test; D006801:Humans; D007262:Infusions, Intravenous; D007328:Insulin / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D012016:Reference Values; D013997:Time Factors
D001786:Blood Glucose; D002247:Carbon Isotopes; D007328:Insulin; D002245:Carbon Dioxide; D003907:Dexamethasone; D005947:Glucose