EFFECT OF 4-WEEK ORAL ADMINISTRATION OF RANITIDINE, A NEW HISTAMINE H₂-RECEPTOR ANTAGONIST, ON PANCREATIC EXOCRINE SECRETION IN RATS

Abstract

The present study was designed to observe the effect of 4-week oral administration of ranitidine, a new histamine H₂-receptor antagonist, on pancreatic exocrine secretion in rats.
As the result, basal pancreatic flow, basal bicarbonate output, and pancreozymin- and secretin-stimulated pancreatic flow in the ranitidine group were significantly lower than those in the control group. On the other hand, there was no significant difference between the two groups with regard to the output of amylase or protein. These data indicate that long-term administration of ranitidine affects the function of epithelial cells of pancreatic ductules only. However, the pancreas in the ranitidine group was histologically normal, and neither serum secretin level before and after duodenal acidification, nor fasting serum gastrin level in the ranitidine group showed a significant difference from those in the control group.
We observed the reduction of pancreatic exocrine secretion after 4-week administration of ranitidine, but the mechanism has not been clarified.