Effect of tolbutamide on the protein secretion of the rat salivary glands.

Protein and amylase content as well as the distribution of isoamylases were determined in the parotid and the submandibular glands of the rat following treatment with tolbutamide for 3-21 days. Significant changes were only observed in the submandibular glands in which, compared with the controls, the amylase activity decreased distinctly after 3 days but had increased 7-fold after 21 days of tolbutamide. These findings could be explained by secretion of epinephrine from the adrenal medulla supposed to take place independently of the effect of insulin and by the possible inhibition of a protein kinase involved in the process of protein secretion from the submandibular gland.