title: Effect of dexamethasone on hepatic glucose and insulin metabolism after oral glucose in conscious dogs.
abstract: To examine whether hyperinsulinemia associated with glucocorticoid treatment results solely from hypersecretion of insulin or also involves altered fractional hepatic extraction, oral glucose (1 g/kg body wt) was administered to dogs with or without dexamethasone treatment (2 mg/d for 2 d). Dexamethasone significantly increased basal glucose and insulin concentrations in the portal vein, hepatic vein, and femoral artery, reduced basal fractional hepatic extraction of insulin from 43 +/- 4% to 22 +/- 4%, and, after oral glucose, increased retention by the liver of net glucose released into the portal system from 27 +/- 4% to 53 +/- 13%. Intraportal insulin infusion (1 and 2 mU/kg per min) after 7 d of dexamethasone treatment (2 mg/d) caused less suppression of endogenous glucose production, and less exogenous glucose was required to maintain an euglycemic clamp than in control animals. Dexamethasone treatment is associated with: decreased basal fractional hepatic insulin extraction contributing to hyperinsulinemia; and less suppression of endogenous glucose production and increase in peripheral uptake in response to insulin, but no reduction in net hepatic glucose uptake after oral glucose.
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology*; D004285:Dogs; D005260:Female; D005947:Glucose / Q000008:administration & dosage / Q000378:metabolism*; D007262:Infusions, Intravenous; D007328:Insulin / Q000008:administration & dosage / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008102:Liver Circulation; D008297:Male
chemical_list: D001786:Blood Glucose; D007328:Insulin; D003907:Dexamethasone; D005947:Glucose