Experimental Studies on the Pathophysiological Changes in the Pancreas of Rat following Bilateral Ligation of the Parotid Gland Duct

The blood sugar level, blood insulin level, serum amylase level and organ amylase level in the pancreas were measured in a total of 110 rats examined at 12, 24, 48, 72 and 96 hr, and 1, 2, 3, 4, and 5 weeks after bilateral ligation of the parotid gland ducts. In parallel with this functional study, light microscopic study of the pancreas and the parotid gland and electron microscopic observations of the pancreas obtained from the rats were performed at the respective periods. The following results were obtained: 1) The serum amylase level was most elevated in the group examined at 12 hr after ligation and it decreased gradually and returned to the normal level at 96 hr after ligation and thereafter. 2) As for the pancreatic exocrine function, the organ amylase level of the pancreas was significantly elevated in the groups examined at 24 hr to 3 weeks after ligation. Electron-microscopically, hyperfunctional state in the pancreatic acinar cells was recognized as evidenced by the dilatation of the granular endoplasmic reticulum. 3) With regard to the endocrine function of the pancreas, the blood sugar level and blood insulin level did not show any significant changes after ligation as compared with the control group. Morphologically, electron microscopy showed a decrease in electron density and swelling of the cored granules, disintegration and fusion of their limiting membranes in the beta cells. These changes are interpreted as indicating the discharge of secretory granules in the beta cells. It is concluded that an impairment of the parotid glands influences the function of the pancreas to a certain degree.