Prostaglandins as biochemical markers of radiation injury to the salivary glands after iodine-131 therapy?

Because salivary glands, as well as thyroid tissue, are able to concentrate radioiodine, the treatment of thyroid diseases with iodine-131 may have secondary effects on salivary gland function which seriously impair the quality of life. Such effects include sialoadenitis and xerostomia. Salivary secretion is stimulated by prosta- glandins (PGs). In this study we evaluate whether 131I therapy influences the levels of PGs in saliva. Patients who had previously received 131I for treatment of hyperthyroidism or differentiated thyroid cancer and healthy volunteers were studied. Levels of PGs [6-oxo-PGF1α, bicyclo-PGEm, thromboxane B2 (TXB2), PGF2α] in unstimulated saliva were measured using enzyme immunoassay. Significantly lower levels of 6-oxo-PGF1α, bicyclo-PGEm and PGF2α and higher levels of TXB2 were found in the group of patients in comparison with the controls. Differences between patients and controls were more pronounced in smokers. This study demonstrates that salivary gland uptake of 131I significantly affects PG levels in saliva.