In order to evaluate the correlation between functional impairment and changes in the expression pattern of immunohistochemical antibodies in the early phase of radiation-induced dysfunction of salivary glands, eight rabbits were scintigraphically examined prior to and 24 h after irradiation with 15 Gy. The parotid glands were studied using HE-staining, Ki-67, alpha-smooth muscle actin (ASMA) and tenascin-C antibodies at every scintigraphic examination. The results demonstrated a significant alteration in the 99mTc-pertechnetate uptake in all irradiated glands. HE-staining showed no relevant impairment of salivary gland tissue in this early phase. Immunohistochemically, we observed a marked re-distribution of ASMA and tenascin-C as well as a reduction of the proliferating rate of acinar cells. This immunohistochemical change correlated with the functional impairment manifested scintigraphically. This study proves the possibility to assess disorders of salivary gland function with immunohistological antibodies as early as 24 h after irradiation and yields the prerequisites to prove the effects of radioprotective agents on salivary gland tissues.