Inhibition of liver glutathione S-transferase placental form-positive foci development in the rat hepatocarcinogenesis by Porphyra tenera (Asakusa-nori)

Cancer Lett. 1999 Jul 1;141(1-2):211-8. doi: 10.1016/s0304-3835(99)00106-8.

Abstract

The effects of Asakusa-nori, Porphyra tenera (PT), a popular edible seaweed in Japan, on the development of putative preneoplastic lesions, glutathione S-transferase placental form (GST-P)-positive foci, in the male F344 rat liver were examined using a medium-term bioassay system. PT significantly decreased both the number and area of GST-P-positive foci in rat livers initiated with diethylnitrosamine (DEN). To investigate possible mechanisms of inhibition, effects of PT on 5-bromo-2'-deoxyuridine (BrdU) labeling in GST-P-positive foci and the surrounding area of hepatocytes were studied. The ratio of the GST-P-positive foci to surrounding tissue labeling indices was decreased in the PT-treated group as compared with the DEN alone group. Ornithine decarboxylase activity in the liver was slightly increased and spermidine/spermine N'-acetyltransferase activity was slightly decreased in the PT-treated animals. These results suggest that PT possesses chemopreventive effects against DEN-induced hepatocarcinogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetyltransferases / metabolism
  • Animals
  • Anticarcinogenic Agents / therapeutic use
  • Body Weight / drug effects
  • Carcinogenicity Tests
  • Cytochrome P-450 Enzyme System / metabolism
  • Food, Fortified*
  • Glutathione Transferase / metabolism*
  • Immunohistochemistry
  • Isoenzymes / metabolism
  • Liver / drug effects
  • Liver / metabolism
  • Liver / pathology
  • Liver Neoplasms, Experimental / chemically induced
  • Liver Neoplasms, Experimental / enzymology*
  • Liver Neoplasms, Experimental / pathology
  • Liver Neoplasms, Experimental / prevention & control*
  • Male
  • Organ Size / drug effects
  • Ornithine Decarboxylase / metabolism
  • Precancerous Conditions / chemically induced
  • Precancerous Conditions / enzymology*
  • Precancerous Conditions / pathology
  • Precancerous Conditions / prevention & control*
  • Rats
  • Rats, Inbred F344
  • Seaweed*

Substances

  • Anticarcinogenic Agents
  • Isoenzymes
  • Cytochrome P-450 Enzyme System
  • Acetyltransferases
  • diamine N-acetyltransferase
  • Glutathione Transferase
  • Ornithine Decarboxylase