Secretion of Calcium by the Salivary Glands in the Dog

¹ Department of Radiation Biology and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York

The mean concentration of calcium in ultrafiltrates of parotid saliva from dogs was more than 1.5 times the mean found in the corresponding serum ultrafiltrates, indicating that the parotid gland was capable of concentrating ultrafiltrable calcium. The values in ultrafiltrates of submaxillary saliva, compared with those of the serum ultrafiltrates, showed no statistically significant differences. After pilocarpine stimulation, the calcium concentration was found to decrease to two thirds and one half of the original values in parotid gland and in submaxillary gland, respectively.

After intravenous or intraperitoneal administration of radioactive calcium, no differences in calcium specific activity were found between blood and parotid saliva evoked by maximal doses of pilocarpine. When pilocarpine doses were reduced, however, there was a delay of more than 1 hour before parotid saliva attained the serum values. The specific activity of the parotid gland calcium was consistently lower than that of the serum or saliva and reached a maximum of 60 percent of serum values in the second hour after isotope administration.

During stop-flow experiments, there was a decrease of specific activity and an increase of calcium concentration in the first sample after flow resumed. At the same time, the opposite was found in the contralateral side taken as a control.