EFFECTS OF X-IRRADIATION ON THE FUNCTION OF RAT SALIVARY-GLANDS AT 3 AND 40 DAYS

The purpose of this study was to examine the effects of different doses of X irradiation on the major rat salivary glands. The flow rates of the salivary glands were measured simultaneously in both parotid and submandibular glands of mature male Wistar rats at 3 and 40 days after head and neck irradiation with single doses of 2.5, 5, 7.5, 10, or 15 Gy. The parotid and submandibular glands were weighed at the time of saliva collection and total body weight was obtained weekly. Significant reductions in parotid salivary flow at 3 days and parotid and submandibular flow at 40 days were found. Diminished saliva output was dose-dependent and significantly reduced at radiation exposures of 7.5 Gy and greater. Submandibular function deteriorated between 3 and 40 days and the extent of hypofunction was comparable to the parotid gland at the latter time. Parotid and submandibular gland weights were reduced by irradiation in a dose- dependent manner at both 3 and 40 days. The effects were similar for both glands at the latter time. Total body weight was also reduced by the head and neck irradiation in a dose-dependent manner. There was significant mortality in the group receiving 15 Gy irradiation between 7 and 14 days after irradiation. The results demonstrate that parotid and submandibular glands may be affected comparably by equal doses of head and neck irradiation when examined at later times. In the period immediately after irradiation, there are significant differences in the responses of the major salivary glands.