Salivary gland changes after isoproterenol-induced enlargement

Abstract

Salivary glands and cardiac ventricles were examined after chronic administration of pharmacological doses of isoproterenol (ISO) to young adult female rats. Enlargement of glands was observed, generally confirming previous reports. Enlargement of ventricles also occurred. Salivary glands were differentially affected, with parotid showing the most, and sublingual the least enlargement. Histological examination revealed increase in cell size sufficient to account for the increase in organ weight, although some mitotic activity was noted. Determination of water, electrolyte, and amylase content of glands indicated the hypertrophy is not due simply to water imbibition; changes in gland composition, when seen, were generally reminiscent, in magnitude and direction, of those occurring ordinarily during function activity. Function after chronic treatment with ISO was little affected; reduction in flow rate after pilocarpine was the major change observed in enlarged glands. Changes in gland and ventricle size and gland composition and function, induced by chronic ISO treatment, were largely reversible by withdrawal of the drug. It appears that in the adult, isoproterenol effects increases in organ size mainly by increase in cell size.