LHR expression in the rat ovaries and uterus. A) Strong LHR immunoreactivity is apparent in mature (MCL) and regressing CL (RCL) and interstitial cells (i). Note unstained vessels (v). B) Strong staining of theca interna (t) and weaker staining of mature granulosa cells (mg) in preovulatory follicle. Note scarce cytoplasmic granules with LHR immunoreactivity in immature granulosa cells (ig). C) Control. D) Increased staining during granulosa cell differentiation (dg) in large antral follicle. E) In the rat uterus, the LHR immunostaining is apparent in the surface epithelium (se), uterine glands (ug) and vasculature (v). Uterine stromal cells show nuclear staining (arrowhead). No hematoxylin counterstain.