Influence of blood osmolality on the concentration of protein and hexosamine in canine saliva.

Abstract

In the present experiments, in an attempt to clarify the mechanism of the influence of the blood osmolality on the electrolyte concentration in saliva, the changes in concentration of the organic component, i. e., protein and hexosamine, in saliva resulting from the intravenous administration of hypertonic solution were studied.The results are as follows:1. Not only electrolyte concentration, but also protein and hexosamine concentration in saliva were increased after the intravenous administration of hypertonic glucose or NaCl.2. The reduction of salivary flow rate appeared together with the increase of blood osmolality, and the concentration of protein, and other constituents in saliva increased. The rate of increase of protein concentration can be explained by the reduction of salivary volume.3. From the relation between the salivary flow rate and the protein excretory rate, it is suggested that the increase of water reabsorption rate through the duct epithelium may play an important role in the increase of protein and hexosamine as well as electrolyte concentration in saliva.4. It was verified by the present experiment using RISA, that the protein was scarcely reabsorbed through the duct epithelium and protein contents in saliva was hardly influenced by the increase of blood osmolality.5. Thus, it is suggested that the previous hypothesis, which explains an increase of concentration of electrolyte in saliva at the state of hypertonicity of body fluid is due to a depressed reabsorption of electrolyte, should be revised.