Luteinizing hormone (LH) and human chorionic gonadotropin (hCG) play an important role in the development and maintenance of male and female gonads.Both these hormones act through the same specific receptor LH/hCG receptor (LHR).Recent studies have shown the existence of functional LHR in several non-gonadal tissues.In mouse uterus at late diestrus stage LH binding sites have been reported earlier.The present study was investigated 1) whether mouse endometrium contain LH receptor mRNA and receptor protein, 2) whether LH can stimulate the expression of LHR mRNA and receptor protein and 3) whether LH can regulate de novo synthesis of 17β-estradiol in this tissue by stimulating P450arom gene expression and P450 aromatase activity.