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CHAPTER 6
Spontaneous Diseases of the Hamster Pancreas
Since the spontaneous alteration of each tissue
seems to represent a primary target for toxic
substances, information on naturally-occurring
tissue abnormalities is important in toxicological
research.
In adult and aged hamsters, hepatocyte
transdifferentiation is common and its frequency is
age- and strain-dependent. The incidence of
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hepatocyte transformation showed a statistically
significant trend by age from 5% to 15-20% with
no significant sex differences. The lesions were
more common in white hamsters than in other
sub-lines. Initially appearing as single or a small
group of cells within or in the periphery of islets
their number increases by time and can occupy
the entire islet and beyond (Fig. 32). In some
Figure 32. Hepatocyte differentiation of islet cells. a) Early stage with a few cells in the islet periphery (arrows).
H&E, X 80. b) A portion of an islet is replaced by hepatocytes. H&E, X 80. c) A large number of hepatocytes
encircling an islet. Some hepatocytes form glands (*). Several ductular structures within hepatocytes (this
animal was treated with pancreatic carcinogen). H&E, X 65. d) top: some hepatocytes show granular
cytoplasm and are present also in ductular epithelium (left middle). Bottom: Reticular changes in hepatocytes.
H&E, X 120. e) Fatty degeneration of hepatocytes, some still showing reticular cytoplasm (top). H&E, X 32. f)
Blood group A antigen expression of hepatocytes. ABC. Anti-A antibody. X 65. g) Fat cell degeneration of
hepatocytes that have replaced the islet. h) Hepatocyte transformation of ductal epithelium. H&E, X 120.