Muscle protein breakdown in liver cirrhosis and the role of altered carbohydrate metabolism.
The rates of muscle protein breakdown, as estimated by the urinary excretion of 3-methylhistidine, were assessed in 30 cirrhotics and 15 controls on a strictly controlled diet. 3-Methylhistidine excretion was increased in cirrhotics irrespective of the etiology of the disease, and correlated with basal glucagon levels and with the insulin/glucagon ratio. In nine cirrhotics and nine age- and sex-matched controls, similar correlations were found between 3-methylhistidine and the areas under 24-hr glucagon or insulin/glucagon curves. A larger amount of 3-methylhistidine was excreted during the nighttime than during the daytime, when glucagon secretion was suppressed and the insulin/glucagon ratio was increased. It is concluded that muscle protein catabolism is increased in cirrhotics, possibly as a result of hyperglucagonemia or the reduced insulin/glucagon ratio. These data agree with the clinical observation of a progressive reduction in lean body mass which becomes evident in an advanced stage of the disease.
D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D050260:Carbohydrate Metabolism; D005260:Female; D005934:Glucagon / Q000097:blood; D006639:Histidine / Q000652:urine; D006801:Humans; D007328:Insulin / Q000097:blood; D008103:Liver Cirrhosis / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009124:Muscle Proteins / Q000378:metabolism*; D010507:Periodicity
D001786:Blood Glucose; D007328:Insulin; D009124:Muscle Proteins; D006639:Histidine; D005934:Glucagon