Figure 4.

 Immunogold localisation of trefoil factor 1 (TFF1) in pre-pit and pit cells of normal adult (P60) oxyntic mucosa. (A) The supranuclear region of a pre-pit cell showing gold particles on the Golgi saccules (G). The contents of two newly produced small secretory granules (arrows) were also covered with gold particles. (B) Close up of the Golgi saccules and upper mucous granule seen in (A). Note the distribution of the black gold particles. (C) Apical cytoplasm of a pre-pit cell (left side) and a differentiating pit cell (right), as seen at the isthmus-pit boundary. The pre-pit cell contained two mucous granules (mg) with pale contents labelled with gold particles. The cell projected a few microvilli (v) facing the gland lumen at the top. The differentiating pit cell contained a group of mucous granules (mg). Gold particles cover their pale contents. Note that at the top, some gold particles (arrows) labelled the exocytosed granule contents. (D) Supranuclear region of a pit cell showing gold particles on the Golgi saccules (G) and the newly produced secretory granules. Some of them contained dense core (arrows). (E) Close up of the right cored secretory granule seen in (A) demonstrating the distribution of gold labelled TFF1. Gold particles were numerous in the dark proteinaceous core. (F) Apical cytoplasm of a pit cell facing the gland lumen showing a large group of many secretory granules. Gold particles were scattered on the contents of all granules and were more numerous in the cored granules. The apical membrane of the cell projected a few short microvilli (v) into the gland lumen seen at the upper right. Note the presence of gold particles on the exocytosed luminal contents. Bars = 100 (B, E), 200 (A, D), and 300 (C, F) nm.