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EXOCRINE PANCREATIC CARCINOGENESIS IN THE GUPPY (POECILIA RETICULATA).
Citation:
Fournie, J W. AND W. E. Hawkins. EXOCRINE PANCREATIC CARCINOGENESIS IN THE GUPPY (POECILIA RETICULATA). Presented at Aquaria Fish Models of Human Disease, Southwest Texas State University, San Marcos, TX, 21-24 September 2000.
Description:
Exocrine pancreatic neoplasms developed in the guppy (Poecilia reticulata) following exposure to the direct acting carcinogen, methylazoxymethanol acetate (MAM-Ac). Fish 6- to 10-days old were exposed to nominal, nontoxic concentrations of 4 and 10 mg MAM-Ac/L for 2 hr and then transferred to carcinogen-free water for grow out. Specimens were sampled monthly up to 9 months to follow the progression of the lesions. No neoplasms occurred in 119 control specimens examined. Pancreatic acinar cell adenomas and carcinomas occurred in 42 of 243 (17%) of the histologically examined specimens. As in earlier studies, specimens exposed to the low MAM-Ac concentration exhibited a higher neoplasm incidence (27.8%) than those exposed to the high concentration (7.8%). Acinar cell adenomas accounted for 27 of the 42 neoplasms. Adenomas exhibited a high degree of acinar cell differentiation and some contained foci of atypical acinar cells that were less differentiated and more basophilic than were surrounding adenoma cells. Carcinomas occurred in 15 specimens and exhibited a range of cellular patterns. Although no distant metastases were found, carcinomas tended to invade neighboring tissues and organs. The occurrence of carcinogen-induced pancreatic neoplasms in guppies strengthens the usefulness of small fish species in carcinogen testing and provides an addition model for studying pancreatic neoplasia.