Effect of acute administration of isoproterenol on submandibular salivary gland of female rat

The functions of salivary glands are under the regulation of both sympathetic as well as parasympathetic nerve fibers. Further, it has also been demonstrated that chronic administration of a beta-adrenergic agonist isoproterenol (IPR) results in hypertrophy and hyperplasia of submandibular gland Schneyer C A, Am J Physiol, 203 (1962) 232]. Specific purpose of the present attempt was to look for metabolic responses of submandibular gland of oestrous female rats at very short intervals after 10 min of administration of 5, 10 and 15 micrograms of IPR to females in oestrous condition; pharmacological action and clearance time being only 8 min. The results indicated significant reduction in case of enzymic activities of phosphorylase, total ATPase and Na(+)-K+ ATPase. Cyclic AMP-specific phosphodiesterase and succinate dehydrogenase activities were suppressed only with 5 micrograms dose, but with rising dose levels the effect was not so apparent. Protein content of the gland was reduced slightly by administration of IPR. Hence, it became clear that submandibular gland responds rapidly to IPR administration. Implications of these observations are discussed.