The effect of local radiotherapy on kallikrein activity in saliva secreted by parotid gland in patients with head and neck cancers

The samples of parotid gland saliva, collected from control human subjects and those taken from patients with head and neck cancers were submitted to the assay of protein concentration and kininogenase and amidolytic kallikrein activities. No patients with parotid gland tumours were included. The effect of pilocarpine stimulation on these parameters was studied. It was found that the saliva secreted by parotid gland of the investigated patients contains less protein and lower kininogenase activity in comparison to control subjects. Pilocarpine administration resulted in an increase of protein concentration and a decrease of kallikrein activity both in control and investigated subjects. Radiotherapy did not evoke any significant changes in spontaneously secreted saliva. The radiotherapy resulted in a progressive decrease of protein concentration and kallikrein activity in saliva secreted by pilocarpine stimulated glands. The kallikrein activity per mg of protein contained in spontaneously secreted saliva increased significantly during radiotherapy but it distinctly decreased in the saliva of pilocarpine-treated patients. It allows to conclude that the parotid glands do not lose their ability to synthesize and secrete kallikrein during radiotherapy of head and neck cancers.