title: Insulin-stimulated rates of glucose uptake in muscle in hyperthyroidism: the importance of blood flow.
abstract: BACKGROUND
  In hyperthyroidism, although hepatic insulin resistance is well established, information on the effects of insulin on glucose uptake in skeletal muscle is variable.
  
  
  METHODS
  To investigate this, a meal was given to nine hyperthyroid (HR) and seven euthyroid (EU) subjects. Blood was withdrawn for 360 min from a forearm deep vein and the radial artery for measurements of insulin and glucose. Forearm blood flow (BF) was measured with strain-gauge plethysmography. Glucose flux was calculated as arteriovenous difference multiplied by BF and fractional glucose extraction as arteriovenous difference divided by arterial glucose concentrations.
  
  
  RESULTS
  Both groups displayed comparable postprandial glucose levels, with the HR having higher insulin levels than the EU. In the forearm of HR vs. EU: 1) glucose flux was similar [area under the curve (AUC)(0-360) 673 +/- 143 vs. 826 +/- 157 micromol per 100 ml tissue]; 2) BF was increased (AUC(0-360) 3076 +/- 338 vs. 1745 +/- 145 ml per 100 ml tissue, P = 0.005); and 3) fractional glucose extraction was decreased (AUC(0-360) 14.5 +/- 3 vs. 32 +/- 5%min, P = 0.03).
  
  
  CONCLUSIONS
  These results suggest that, in hyperthyroidism, insulin-stimulated glucose uptake in muscle is impaired; this defect is corrected, at least in part, by the increases in BF.
authors: Second Department of Internal Medicine, Research Institute and Diabetes Center, Athens University, Attikon University Hospital, 1 Rimini Street, Haidari, Greece. gdimi@ath.forthnet.gr
authors: George
authors: G
authors: Dimitriadis
authors: Panayota
authors: P
authors: Mitrou
authors: Vaia
authors: V
authors: Lambadiari
authors: Eleni
authors: E
authors: Boutati
authors: Eirini
authors: E
authors: Maratou
authors: Eftychia
authors: E
authors: Koukkou
authors: Demosthenes
authors: D
authors: Panagiotakos
authors: Nikos
authors: N
authors: Tountas
authors: Theofanis
authors: T
authors: Economopoulos
authors: Sotirios A
authors: SA
authors: Raptis
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D005215:Fasting / Q000097:blood; D005260:Female; D005542:Forearm / Q000098:blood supply; D005947:Glucose / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D006980:Hyperthyroidism / Q000378:metabolism*; D007328:Insulin / Q000032:analysis / Q000494:pharmacology*; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply / Q000187:drug effects / Q000378:metabolism*; D017534:Radial Artery / Q000737:chemistry / Q000187:drug effects / Q000502:physiology*; D012039:Regional Blood Flow / Q000502:physiology
chemical_list: D001786:Blood Glucose; D007328:Insulin; D005947:Glucose