The effect of cyclophosphamide and vincristine on intestinal protein loss in rats.

24 and 48 hours after a single intraperitoneal dose of 80 mg/kg cyclophosphamide (I. group) and 0.20 mg/kg vincristine (II. group) the intestinal protein loss has been studied using the 51CrCl3 isotope method. 16 animals were used as control (III. group). In case of both cytostatics, the intestinal protein loss was significantly higher. Histologically the small bowel mucosa, on the first day after injection, showed, in the crypts, necrotic cells and mitoses arrested in metaphase. By the second day, after injection, severe villous atrophy and occasional mucosal erosions were seen. The causes of these changes are discussed together with the question of the disrupted barrier function of the small bowel.