Daunomycin is a member of the anthracycline class of antitumor antibiotics. And it was isolated from cultures of Streptomyces peuccetius in 1963.
Chemically, it was found to consist of a pigmented aglycone (daunomycinone) bound to an aminosugar, daunosamine.
The biochemical mode of cytotoxic action of daunomycin results from its binding to DNA possibly by intercalation between the base pairs, thereby inhibiting the DNA polymerases.
The author has investigated the effect of daunomycin on the mouse liver histochemically observing the change in the activity of alkaline phosphatase. The animals treated with 16 mg per kg of daunomycin were sacrified at 6, 12, 24 and 36 hours after drug administration. The animai&of control group were administered on-ly water for injection. The liver specimens were fixed in 10%-neutral formalin at 4´C and sectioned at 1612 in thickness in a frozen cryostat. The activity of alkaline phosphatase was evaluated histochemicaily by Gomori´s method.
The results were as follows.
1. The activity of alkaline phosphatase was moderate positive at the periportal and intermediate zones and trace positive at the centrilobular zone of the hepatic lobule in 6 hours daunomycin treated group. As the time goes by, the activity of alkaline phosphatase was decreased in the hepatic lobule. At 24 hours after administration of daunomycin, negative reaction at the centrilobular zone, trace positive at the intermediate zone and weak positive at the periportal zone of the hepatic lobule were seen.
Consequently, it is suggested that daunomycin decreases the activity of alkaline phoshatase in the liver, due probably to its cytotoxic effect on the hepatocyte.
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