[Localization of insulin-like protein in the submaxillary glands of laboratory animals]

Insulin-like protein (ILP) was extracted from the submaxillary glands of cats, guinea-pigs and male rabbits. As shown by radioimmunoassay, it is localized in the cells of the striated ducts of the salivary tubes. ILP is likely to be related to small granules visible under electron microscope. These granules are largely located in the apical parts of the cells. The amount of ILP (immunoreactive insulin per Ig crude weight of the glands was determined. The content of immunoreactive insulin was found to be higher in submaxillary glands (over than by 60 times) as compared with blood serum but less than in the pancreas. The electrophoretic properties of ILP are similar to those of reference human and bovine insulin. It is suggested that the submaxillary glands participate in the maintenance of insular homeostasis.