The content of glycogenolytic factor in pancreas from different species.

Assays of glycogenolytic factor in samples of insulin prepared from the pancreas of ox, sheep and pig (Audy & Kerly, 1952) suggest that there is little difference in the glycogenolytic-factor content of pancreas from these animals. In an attempt to find a richer source of the factor, extracts of pancreas from cats, rats, ferrets and guinea pigs have been assayed for their glycogenolytic-factor content. Rabbit pancreas was also examined for comparison with the results of Sutherland & Duve (1948), who assayed the factor content of pancreas from rabbit, dog and ox. Since Sutherland & Duve (1948) and Heard, Lozinski, Stewart & Stewart (1948) have suggested that the factor is secreted by the a cells of the pancreas, assays were also carried out on extracts of tissue from the teleost fish Lophius piscatorius, a species in which islet tissue occurs separately from the pancreas proper, mostly in easily recognizable encapsulated structures (Mollendorf, 1939).