SIGNAL-TRANSDUCTION MECHANISM IN RESPONSE TO AFLATOXIN B-1 EXPOSURE -PHOSPHATIDYLINOSITOL METABOLISM

A single dose of aflatoxin B-1 (7 mg/kg body weight) to male Wistar ra ts significantly stimulated the hepatic activity of phosphatidylinosit ol kinase, a key enzyme in the cell signalling mechanism, 1-7 h follow ing its administration. Phosphatidylinositol 4-phosphate kinase activi ty showed only marginal increase, whereas activities of diacylglycerol kinase and phosphatidylinositol synthetase remained unchanged. The le vel of diacylglycerol, however, recorded a sharp increase at 1 and 2 h after carcinogen treatment. The stimulation of phosphatidylinositol c ycle with faster turnover of active second messengers might be an earl y step in the manifestation of toxicity and/or carcinogenicity.