Preliminary observations on the mitogenic effect of cyclopropenoid fatty acids on rat pancreas.

Male Sprague-Dawley rats were fed a diet containing 500 ppm of cyclopropenoid fatty acids (CPFA). After 2 weeks, mitotic activity and [3H]thymidine incorporation into DNA were significantly increased in pancreatic acinar cells. Continued feeding of the diet for 4 and 8 weeks led to decreasing mitotic activity which was still significantly increased over that of control animals. Focal necrosis of acinar cells was histologically apparent after 8 weeks of CPFA ingestion. Ultrastructural evidence of focal cytoplasmic injury was detected in acinar epithelial cells as early as 2 weeks after feeding of the CPFA diet was begun. A difference in dose response to CPFA appears to exist between Sprague-Dawley and Fischer F344 rats in that the latter, a dose of CPFA (5 mg/100 g body weight), did not evoke a mitogenic response.