Appearance of a carcinoid-like pattern in rat hepatic tumors induced by 3'-methyl-4-dimethyl-aminoazobenzene.
This study investigated the histological distribution of argyrophilic cells in experimental hepatic neoplasms, the number of these cells, and the proportion of neoplasms with such cells. Seventy 6-week-old male Donryu rats were given a 0.06% 3'-methyl-4-dimethyl-aminoazobenzene (3'-MeDAB) diet for 10 weeks, followed by an ordinary diet for an additional 10 weeks. Of the 70 rats, 50 were used for this investigation; 29 had hepatic tumors, 18 had cholangiofibrosis, and the other three had oval cell proliferation only. Hepatic tissues were stained with Grimelius and Fontana-Masson stains as well as routine hematoxylin-eosin stain. Argyrophilic cells were found in the hepatic neoplasms of 8 rats without argentaffin cells, while cholangiofibrosis was associated with argentaffin cells in almost all cases. Of the 8 rats with argyrophilic cells, three had an abundant population of these cells. The argyrophilic cells were found in areas of the neoplasms with a glandular, trabecular, tubular, or poorly differentiated pattern. Electron microscopy revealed that the neoplastic cells with a positive argyrophil reaction contained small round electron-dense endocrine granules. In addition, in the areas of cholangiofibrosis, two different types of gut endocrine cells were present (G and EC cells). These results suggest that 3'-MeDAB might induce hepatic carcinoid under certain conditions, though we have yet to confirm the development of a pure hepatic carcinoid due to this substance.
Karaki
Y
Y
Second Department of Surgery, Toyama Medical and Pharmaceutical University.
Munakata
S
S
Saeki
T
T
Hirota
S
S
Fujimaki
M
M
D000818:Animals; D002276:Carcinoid Tumor; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced / Q000473:pathology* / Q000648:ultrastructure; D008297:Male; D008749:Methyldimethylaminoazobenzene; D051381:Rats; D012834:Silver; D004124:p-Dimethylaminoazobenzene
D012834:Silver; D008749:Methyldimethylaminoazobenzene; D004124:p-Dimethylaminoazobenzene