[Methods and clinical significance of an oral tolerance test of essential trace element, especially an oral zinc tolerance test].

Oral administration of zinc (zinc tolerance test) was performed in 6 healthy adults, 11 patients with chronic hepatitis and 17 patients with liver cirrhosis to evaluate the ability of the digestive organs in patients with chronic hepatic diseases to absorb zinc. That is 300 mg of zinc sulfate powder (ZnSO4 7H2O)--equivalent to 68 mg of zinc--was dissolved in 200 ml of physiological saline solution, and the subjects received oral administration of the solution in a fasting condition during the early morning. The mean levels of serum Zn (ppm) at 0, 1, 2, and 3 hours after the test dose of ZnSO4 were 0.8 +/- 0.06, 1.66 +/- 0.21, 2.73 +/- 0.22 and 2.53 +/- 0.33 in cirrhotic patients, respectively. In most subjects, serum Zn levels peaked at 2 or 3 ours. The increase in serum Zn at 60 minutes during the base line Zn tolerance test was similar in patients and controls. The area under the curve was also significantly decreased in cirrhotic patients. These results will confirm the presence of diminished absorption by the intestinal tract in patients with liver cirrhosis.