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.

Possible significance of anogenital licking by female rat during precopulatory behavioural patterns.

Possible significance of licking of anogenital region by female rat in the initial steps of precopulatory behaviour was studied in short bouts of 3 min each. The order of conspicuous events was--(1) exploratory behaviour, (2) partners pursuing each other, (3) head-to-tail orientation and mutual licking of anogenital regions; particularly when females were in oestrous and metoestrous stages and (4) obvious avoidance and even aggressive behaviour by female during dioestrous stage.

Early effects of spaying on plasma and liver phospholipid concentrations in rats.

Effect of spaying on liver and plasma phospholipid components was studied in 4-day cyclic rats (Haffkin Institute Strain). Rats were ovariectomized during diestrous stage of estrous cycle. Ovariectomy (OVX) was shown to increase the total phospholipid content in both the liver lobes after 24 hr interval, it remained higher in spigelian lobe up to 72 hr but it was lowered in the right lobe at 48 hr interval. Concentration of sphingomyelin (SHP) in total phospholipids, as assessed by TLC, was slightly increased in both lobes after 48 hr of spaying. It declined significantly by 72 hr only in the spigelian lobe. Phosphotidylcholin, phosphatidylserine and phosphatidylethanolamine concentrations showed fluctuating pattern up to 48 hr of spaying, but most of these changes were seen to be restored to the normal level by 72 hr interval. Results indicate that the relative lack of ovarian hormones due to ovariectomy have obvious influence on hepatic lipid metabolism particularly that of phospholipid components. There appears to be an inverse relationship between hepatic lipid components and blood plasma. Spigelian lobe exhibits distinctly different responses to ovariectomy as compared to those of the right lobe. Maximal alterations are observable by 48 hr post-OVX interval.

Influence of oestrous cyclicity on some aspects of carbohydrate metabolism of the submandibular salivary gland of the albino rat.

Titres of oestrogen are known to rise from dioestrous to proestrous stage of the oestrous cycle. Such a rising level of estrogen may be responsible for rise in intracellular concentration of cAMP. The estrogen primed tissue, changing from proestrous to oestrous, under known increasing progesterone level and preovulatory LH surge, may led to a sort of balancing action on the varying levels of glycogen synthetase and phosphorylase enzyme activities so as to play a role in maintaining a steady state of glycogen concentration in the salivary gland. Therefore, alterations in glycogen concentration and the activities of concerned enzymes viz. glycogen synthetase, phosphorylase and cAMP-specific phosphodiesterase (cAMP-PDE) have been studied in albino rats. An abrupt but significant drop in cAMP-specific phosphodiesterase (cAMP-PDE) activity was found to facilitate corresponding reduction in glycogen and lowering protein concentration of the gland, during transition from oestrous to metoestrous. Main features of the meteostrous stage were depletion of glycogen and protein concentration. Taking into consideration the alteration of glandular glycogen and protein concentration, during various stages of oestrous cycle, variation in the viscosity of saliva has been suggested; in phase with the cyclicity.