Objective To study the localization of luteinizing hormone(LH), its receptor (LHR) and their mRNA in submaxillary gland of rats, and to provide a theoretic evidence for further studying functional significance of the LH in submaxillary gland. Methods Immunohistochemical methods and in situ hybridization methods were used in the experiment. After isolation of the total RNA from the submaxillary gland, RT-PCR was conducted to obtain LH and LHR cDNA by using the degeneration primers. The products of PCR were analyzed by sequencing with Sanger’s method, respectively. Results The epithelial cells of serous acinus in submaxillary gland of rats showed LH and LHR immunoreactivity, which were located in cytoplasm with negative nuclei. LH and LHR mRNA hybridized signals were also detected in cytoplasm in the above cells. LH cDNA sequence was identical to that of the LH which has been reported in rat pituitary, and LHR cDNA sequence was identical to that of the LHR which has been reported in rat testis.Conclusion The epithelial cells of serous acinus in submaxillary gland of rats may not only produce LH but also be its target cells. LH may be involved in the functional regulation of submaxillary gland through autocrine o