COMPARATIVE TOXICITY IN THE RAT OF CYTOCHALASIN-B AND CYTOCHALASIN-E

T. Glinsukon and S. Lekutai. Comparative toxicity in the rat of cytochalasins B and E. Toxicon 17, 137-144, 1979.-Cytochalasins B and E, produced by molds, were acutely toxic to rats. The ld50 values for a single i.p. administration of cytochalasin B were: one-day-old rats, 10.6 mg/kg and weanling rats, > 15 mg/kg. Comparable values for cytochalasin E were: one-day-old rats, 1.28 mg/kg and weanling rats 3·5-5·0 mg/kg. One-day-old rats receiving a lethal i.p. dose of either cytochalasin B or E died within 2-8 hr with 0·3 ml fluid in the peritoneal cavity. Histopathologic changes with cytochalasin E included severe congestive necrosis of the liver and kidney whereas cytochalasin B caused congestion only at the edge of the liver. Cytochalasins E (0·5 mg/kg) and B (1·5 mg/kg) produced a maximum decrease of 46·2% and 45·4% respectively in total plasma protein concentrations when a single i.p. dose was given to adult male rats. Cytochalasin B caused a transient reduction in plasma volume within the first hr after administration and the volume gradually increased to the normal value. Maximum reduction of plasma volume and mean arterial pressure occurred 90 min after treatment with either cytochalasin B or E. Cytochalasin B appears to act directly on the walls of blood capillaries permitting extravascular effusion of plasma fluid. It also induces qualitatively different histopathologic changes in the liver and kidney than cytochalasin E. © 1979.