Ultrastructural investigation of the effect of mitomycin C on the rat exocrine pancreas.

In order to clarify the pathophysiology of digestive disorders which are caused with anticancer agents, Mitomycin C was intravenously administrated to rats and the ultrastructure of the pancreas was studied. The alteration of acinar cells after under 4 daily administrations of 1.0 mg/Kg of Mitomycin C was not remarkable and in an early stage returned to normal structure. In above 8 daily administrations of 1.0 mg/Kg of Mitomycin C, however, pronounced degeneration of acinar cells was induced and acinar cells did not recover to the previous level, but die within one month. The ultrastructural changes induced by Mitomycin C were mainly aggregation of chromatin in the nuclei, tubularly dilatation of the rough endoplasmic reticulum, and swelling of the mitochondria. It was surmised that the biosynthesis and supply of protein such as digestive enzymes were not amply carried on; hence, the ehcmotherapy could give rise to severe digestion disorders. It appeared necessary to further study the dosage and dosage schedule of the anticancer agents, along with the necessity for taking ample care of patients presenting such disorders.