Inhibition of liver glutathione S-transferase placental form-positive foci development in the rat hepatocarcinogenesis by Porphyra tenera (Asakusa-nori).
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.
Ichihara
T
T
Department of Pathology, Osaka City University Medical School, Osaka, Japan.
Wanibuchi
H
H
Taniyama
T
T
Okai
Y
Y
Yano
Y
Y
Otani
S
S
Imaoka
S
S
Funae
Y
Y
Fukushima
S
S
D000123:Acetyltransferases / Q000378:metabolism; D000818:Animals; D016588:Anticarcinogenic Agents / Q000627:therapeutic use; D001835:Body Weight / Q000187:drug effects; D015197:Carcinogenicity Tests; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D005527:Food, Fortified; D005982:Glutathione Transferase / Q000378:metabolism*; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced / Q000201:enzymology* / Q000473:pathology / Q000517:prevention & control*; D008297:Male; D009929:Organ Size / Q000187:drug effects; D009955:Ornithine Decarboxylase / Q000378:metabolism; D011230:Precancerous Conditions / Q000139:chemically induced / Q000201:enzymology* / Q000473:pathology / Q000517:prevention & control*; D051381:Rats; D011916:Rats, Inbred F344; D012624:Seaweed; D000099228:Diamine N-Acetyltransferase
D000123:Acetyltransferases; D016588:Anticarcinogenic Agents; D003577:Cytochrome P-450 Enzyme System; D005982:Glutathione Transferase; D007527:Isoenzymes; D009955:Ornithine Decarboxylase; D000099228:Diamine N-Acetyltransferase