Expression and localization of luteinizing hormone receptor in the female mouse reproductive tract

The presence of the LH receptor (LHR) in nongonadal tissues of the reproduc tive tract has been reported, but localization studies have not been perfor med. Our objectives were to demonstrate the presence of LHR in the reproduc tive tract and to localize receptor expression. Reproductive age rats and m ice were obtained and I-125-hCG binding assays were performed on membrane p reparations from the uterus, ovary, liver, and testis. In situ hybridizatio ns were performed using S-35-labeled antisense and sense RNA probes prepare d from nucleotides 1-591 of the mouse LHR cDNA. Specific hCG binding was de tected in membrane preparations from the ovary, uterus, and testis but not in the liver in both the rat and mouse. In the ovary, LHR mRNA was localize d in theca cells, large follicles, and corpora lutea as expected. In the ut erus, LHR mRNA was expressed in stromal cells of the endometrium and in the uterine serosa. Uterine smooth muscle cells had low levels of expression, and the endometrial epithelium was negative. In the oviduct, high levels of LHR expression were noted on the serosa and in subepithelial cells. Oviduc tal smooth muscle had low expression, and the epithelium was negative. We c onclude that functional, nongonadal LHR are expressed in the mouse reproduc tive tract. The presence and localization of LHR expression in the mouse re productive tract lay the foundation for transgenic models to address the ph ysiologic role of these receptors.