[Absence of effect of propranolol on urinary excretion of 3-methylhistidine in hyperthyroidism].
Lean body mass and muscle protein breakdown were evaluated in euthyroid and hyperthyroid subjects by measuring the urinary excretion of creatinine and 3-methylhistidine. Since catecholamines probably have an inhibitory effect on muscle protein catabolism through a beta-receptor mechanism, the effects of propranolol on 3-methylhistidine excretion were also evaluated in hyperthyroid subjects. Hyperthyroid subjects had a lower lean body mass (34.9 +/- 6.3 kg versus 47.7 +/- 8.9 kg, p less than 0.001) and a greater 3-methylhistidine excretion (25.1 +/- 7.4 versus 19.0 +/- 4.8 mumol/mmol creatinine, p less than 0.05) than euthyroid subjects. Propranolol administered orally to hyperthyroid subjects decreased pulse rate (p less than 0.01) and plasma triiodothyronine concentrations (from 5.40 +/- 2.28 to 3.61 +/- 1.61 nmol/l, p less than 0.01), but did not modify urinary 3-methylhistidine excretion (24.8 +/- 8.7 versus 25.1 +/- 7.4 mumol/mmol creatinine). These results suggest that muscle wasting in hyperthyroidism is related to increased protein catabolism. This increased protein breakdown is not modified by short term administration of propranolol, a beta-blocking agent widely used in the management of hyperthyroidism.
D000328:Adult; D003404:Creatinine / Q000652:urine; D005260:Female; D006639:Histidine / Q000031:analogs & derivatives*; D006801:Humans; D006980:Hyperthyroidism / Q000378:metabolism / Q000652:urine*; D008297:Male; D008762:Methylhistidines / Q000652:urine*; D008875:Middle Aged; D009124:Muscle Proteins / Q000378:metabolism; D011433:Propranolol / Q000494:pharmacology*
D008762:Methylhistidines; D009124:Muscle Proteins; D006639:Histidine; D011433:Propranolol; D003404:Creatinine; C028118:3-methylhistidine
Absence d'effet du propranolol sur l'élimination urinaire de la 3-méthylhistidine dans l'hyperthyroïdie.