Insulin sensitivity in hyperthyroidism: measurement by the glucose clamp technique.
Sensitivity to porcine insulin has been compared in overnight fasted hyperthyroid and control subjects using a euglycaemic clamp technique. Basal values for blood glucose, lactate, pyruvate, alanine, serum insulin and C-peptide were similar in the two groups, whilst blood glycerol (hyperthyroid 0.11 +/- 0.02 (mean +/- S.E.) vs. control 0.06 +/- 0.01 mmol/l, P less than 0.01) and blood 3-hydroxybutyrate (0.28 [0.03-0.79, range ]vs 0.09 [0.01-0.29 ]mmol/l, P less than 0.05) were increased in hyperthyroidism. During the 2 hour insulin infusion (0.05 U/kg/h), serum insulin plateaued at the same level (44 +/- 4 vs 44 +/- 1 mU/l) and insulin metabolic clearance rates were similar (1.21 +/- 0.10 vs 1.25 +/- 0.03 l/min). Serum C-peptide levels also decreased by similar amounts (40 +/- 8 vs 47 +/- 6%). The amount of glucose infused to maintain euglycaemia was identical during the second hour of insulin infusion (290 +/- 50 vs 330 +/- 30 mg/kg) as were the increments in lactate and pyruvate concentrations. Blood glycerol values decreased in both groups although values in hyperthyroid patients remained significantly higher than in controls. 3-Hydroxybutyrate concentrations fell to similar values in the two groups. These findings suggest that insulin-stimulated glucose metabolism and inhibition of ketogenesis are normal in hyperthyroidism.
D020155:3-Hydroxybutyric Acid; D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D002096:C-Peptide / Q000097:blood; D005260:Female; D005947:Glucose / Q000494:pharmacology; D005990:Glycerol / Q000097:blood; D006111:Graves Disease / Q000097:blood*; D006801:Humans; D006885:Hydroxybutyrates / Q000097:blood; D007263:Infusions, Parenteral; D007328:Insulin / Q000097:blood / Q000494:pharmacology*; D007773:Lactates / Q000097:blood
D001786:Blood Glucose; D002096:C-Peptide; D006885:Hydroxybutyrates; D007328:Insulin; D007773:Lactates; D005947:Glucose; D005990:Glycerol; D020155:3-Hydroxybutyric Acid