Effects of 5-fluorouracil on exocrine glands. III. Fine structure of Brunner's glands of rats.

Effects of a pyrimidine analogue, 5-fluorouracil (Fur), have been studied by electron microscopy and by electron microscopic cytochemical techniques. Previous studies have demonstrated that rats show serious gastrointestinal disturbances 5 days after 3 daily injections of FUR (50 mg/kg). The present investigation demonstrates that Brunner's glands under the same conditions suffer certain cytological changes involving the Golgi apparatus, where a notable reduction in the number of Golgi stacks is observed. The vacuolar components in the Golgi complex appear empty. Cytochemical localizations of uridine diphosphatase and thiamine pyrophosphatase activities, however, are normal. The reaction products are localized in the distal two or three lamellae of the Golgi stack and within the secretory granules nearby. In addition reaction products are present along the apical plasma membrane on the luminal side, suggesting a possible movement of these membranes from the Golgi stack, via secretory granules, to the apical plasma membrane.