Abstract
The relationship between functional maturation and sex differences in rat submandibular gland during (2-10 weeks of age) was studied. The secretory properties stimulated by the specific α1-adrenergic agent, methoxamine, were compared with those by pilocarpine.
The volume of total saliva (during 60 min) was independent of sex, whereas it correlated with the wet weight of the gland. Characteristic differences appeared in the flow rate of saliva, and the concentration of saliva proteins and inorganic ions during development and between the sexes. A positive correlation was observed between saliva Ca2+ and protein concentrations in the postnatal changes irrespective of sex differences. This finding suggested that the stimulation of α1-adrenergic receptors and the release of Ca2+ might be correlated with the secretion of saliva proteins. In the comparison of the disk gel electrophoresis profiles of saliva proteins, characteristic changes were observed according to the growth, although not in sex differences. These changes were clearly distinguishable from the response to parasympathomimetics.
The effects of α1-adrenergic antagonists on the stimulation of the α1-adrenergic receptors were observed from 2 weeks of age. The gland cyclic-GMP content reached the adult level in 3-4 week old rats, but lowered temporarily in 5 week old ones, and then recovered. Only in 2 week old rats was the increase of cyclic-GMP content corresponding with the stimulation seen, and the response to isoproterenol was also observed in the same age. On the other hand, the increase of cyclic-AMP was seen in 3 week old rats, corresponding with both α- and β-adrenergic receptor stimulations. These results indicate that the various functional changes in rat submandibular gland are correlated with its celldifferentiation.
