LHR immunostaining in porcine tissues. A–C) Preovulatory follicles (late follicular phase) show a transition from granular cytoplasmic to surface LHR immunoreactivity in granulosa cells (arrowheads), lack of staining of vascular layer, increase of LHR staining in theca interna and extreme dilatation of follicular microvasculature (v). D) Control for C. E) Mature CL. F) Old CL. G) Ovarian surface epithelium (arrowhead). H) Fallopian tube (FT). I) Skin vessels show strong LHR immunoreactivity of the entire vascular wall (arrowhead). J) In ovarian vasculature, the LHR immunoreactivity is limited to the nuclei of some endothelial cells (arrowhead) but other components of vascular wall are unstained. Insets in E–J show control staining. Details in text. Hematoxylin counterstain except panels A–D, H and I.