Figure 7.
Immunoelectron microscopy of SgIII and CgA in (A) AtT-20 cells and (B–D) male rat pituitary gonadotropes. (A) Two sizes of colloidal gold particles indicative of CgA (5 nm gold) and SgIII (10 nm gold) were colocalized in most secretory granules in the AtT-20 cell (arrows). (B) Gold particles indicative of SgIII (15 nm gold) were observed restrictedly on the large-type secretory granules (arrows) in the male rat gonadotropes. (C) Gold particles indicative of SgIII (20 nm gold) were localized in the granules labeled with anti-CgA (10 nm gold; arrows) but (D) not in those labeled with anti-SgII (10 nm gold; arrowheads). (B–D) LH was simultaneously labeled with smaller gold particles (5 nm gold) in these ultrathin sections. (B and C) Small granules with LH were indicated by an arrowhead. Bars, 200 nm.