Ultrastructural analysis of pancreatic carcinogenesis. VI. Early changes in hamster acinar cells induced by N-nitroso-bis(2-hydroxy-propyl)amine

: Male Syrian golden hamsters were given weekly s.c. injections of 250 mg/kg body weight of N-nitroso-bis(2-hydroxypropyl)amine (BHP) for up to 15 weeks. Electron microscope studies were carried out on early changes in the exocrine pancreas of these hamsters for 2 weeks to 15 weeks. The majority of observed alterations occurred in the acinar cells and included the appearance of "dark" and "light" cells, the former showing nuclear shrinkage and irregularity but maintaining a normal rough endoplasmic reticulum (ER) and zymogen content. The "light" cells exhibited a variety of early fine structural alterations including conformational changes in their rough ER, together with a reduction in zymogen granules, increased autophagic vacuoles and Golgi hypertrophy. Ducts and ductules were relatively unaffected. The observations indicate that the acinar cells were most affected, morphologically, by BHP and are consistent with the view that these cells are the primary target for BHP.