Histophysiology of the pancreatic islets of Rana tigrina, treated with glucagon.

The effect of mammalian crystalline glucagon (0.5 mg and 2.0 mg/kg) on the blood glucose level and pancreatic islets of Rana tigrina was studied at different stages after its treatment. This frog is moderately sensitive to glucagon and exhibits hyperglycemia and regressive changes, primarily in the beta- and secondarily in the alpha-cells of the islet tissue. The effectiveness of the hormone depends upon the dose employed. The restricted damage in only a fraction of the alpha-cells indicates that this fraction is like the glucagon secreting alpha2-cells of mammals and is the source of glucagon in Rana tigrina also.