Luteal neurophysin in the nonpregnant cow and ewe: immunocytochemical localization in membrane-bounded secretory granules of the large luteal cell.

The highly conserved neurophysin associated with neurohypophysial hormones was localized in the large luteal cell of the nonpregnant cow and nonpregnant ewe with light microscopy avidin-biotin immunohistochemistry. Furthermore, with rabbit anti-oxytocin-neurophysin serum and goat anti-rabbit immunoglobulin G-colloidal gold, neurophysin was localized in the 100- to 200-nm diameter membrane-bounded secretory granules of the large luteal cells.