PAROTID SECRETION OF PROTEIN IN MAN

Abstract

In unstimulated saliva, total protein concentration averaged 186 mg per 100 ml and amylase activity 46 units per 100 ml. The protein concentration was lower in the early morning than at midday. After dilute acetic acid stimulation, both total protein concentration and amylase activity were increased but the concentrations were not affected by rates of secretion above 0.1 ml per minute. Unlike protein, the potassium concentration fell with stimulation. Using zone electrophoresis on filter paper, as many as nine protein components were found, none of which corresponded to the serum proteins. The amylase activity was restricted to a component of low mobility which moved to the anode. There were two or three bands containing glycoproteins; all moved towards the cathode. There were qualitative and quantitative differences between stimulated and unstimulated secretions. Saliva collected 2 or 24 hours after a tracer dose of I131 showed less than 1% residual radioactivity after dialysis or treatment with an anion exchange resin, indicating that little if any of the salivary iodide is organically bound.