DISTURBANCES OF CYSTINE METABOLISM IN LIVER DISEASE

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Abstract
By the use of polarography, plasma cystine levels and urine cystine excretion were determined in normal subjects and patients with acute and chronic liver disease. The normal fasting plasma cystine level was 10.64 + 1.87 [mu]g/ml; in patients with cirrhosis, 13.7 [plus or minus] 5.75. The normal range of urine cystine was 40-70 mg/24 hours in men and 30-50 mg in women. In male patients with cirrhosis it was 38-234 mg/24 hours and in females 32-150 mg. In patients with acute hepatitis it was 76-134 mg/24 hours. Tolerance tests were also carried out with oral doses of 5.0 g of L-cystine or 3.0 g of L-cystine HC1. The plasma cystine levels were followed over a 6-hour period. The patients with cirrhosis handled cystine almost as well as the controls but showed a markedly "diabetic" type of curve after taking cysteine. This was attributed to liver damage and not to large portal-systemic anastomoses. The renal clearance of cystine was about.2-4 ml/minute in the controls and the patient with liver disease.