Effects of some drugs on islet function in catfish.

Blood glucose variations and concomitant bioptical cytopathological changes in the pancreatic islets following treatment with certain drugs were studied in the catfish. Glucose loading produced a dose-related hyperglycemia, maximum within 3 hr, while alloxan caused a biphasic rise in glucose level without induction of permanent diabetes. Streptozotocin elicited a monophasic hyperglycemic state at a lower dose and biphasic response at higher doses. Glybenclamide produced hypoglycemia in normal and sham-operated fish; the depancreatized animals were unresponsive to this treatment. In all the cases, normoglycemic values were restituted within 4 days of the treatment. The beta-cells of the islets underwent varying histopathological changes with signs of regenerative activity. A depletion in heavy metal (zinc) in these cells was also evident after treatment with streptozotocin.