Histopathology of the endocrine pancreas of a fresh-water fish, Clarias batrachus (L.). V. Effect of epinephrine administration.

Intramuscular administration of epinephrine in 2 mg/kg and 5 mg/kg body weight doses to Clarias batrachus caused significant hyperglycemia between 12 and 18 h after treatment. The hormone produced a small decrease in the liver glycogen, but induced a notable fall in the glycogen of muscles and a transient increase in the brain glycogen. Light-microscopical examination of the pancreatic islets revealed degranulation and vacuolization of the beta-cells accompanied by acute necrosis. Damage to the alpha-cells was also noticed in hyperglycemic fish. The changes in the cellular configuration of the islets, blood glucose and on the tissue glycogen contents were dose-dependent. It is suggested that epinephrine alters the carbohydrate metabolism through the alpha-cells of the islets.