ABSORPTION, DISTRIBUTION AND EXCRETION OF NEOCARZINOSTATIN (NCS) IN MICE AFTER ORAL ADMINISTRATION

Abstract

Distribution, excretion and toxicity of an antitumor protein, neocarzinostatin (NCS) were examined in mice after oral administration. The oral LD₅₀ was 1 g/kg compared to 1 mg/kg after intravenous injection. After oral administration of 200 mg/kg of NCS, the tissue level was low but detectable in lung, skin and pancreas in addition to the tissues of the gastrointestinal tract. The NCS level in lung and skin remained constant through 6 hours. In gastrointestinal tissues after oral administration the level was higher in the stomach than the large intestine or small intestine. The total recovery of orally administered NCS in feces of mice was 26.5% of the given dose during the first 12 hours. Inactivation of NCS by homogenates of small and large intestines (about 50%) was found in in vitro experiments.