Abstract
After an oral administration of 18 mg/kg of methylarsine sulfide, the distribution of arsenic in blood and tissues, the excretion of arsenic in feces and urine, its effect on liver constituents including microsomal phospholipids and cytochromes, and drug-metabolizing enzyme activities were examined. The blood level of arsenic reached the maximum 3 days after dosing and decreased at a slow biological half-life of 50 days. The distribution of arsenic in tissues also attained the maximum at 3 days and more than 2 % of the dose was found at 120 days. Excretion of arsenic in feces was 33.4% during the first 4 days and a trace amount of arsenic was detected in bile. The urinary excretion of arsenic was about 7% of the dose during the first 3 days, 18% during 30 days, and still remained at 120 days. Methylarsine sulfide reduced the cytochrome P-450 content, aminopyrine demethylase activity, and spectral change with aniline binding. Enzyme activities per P-450 were not changed. In hepatic microsomal phospholipids, the percentage composition remained unchanged but the total content and the percentage of unsaturated fatty acids decreased by the effect of methylarsine sulfide.
