The fine structure of Brunner's glands in the rabbit

AbstractThe fine structure of the duodenal glands of Brunner in the rabbit has been examined. The glands, which are concentrated within the submucosa, are composed of tubules that open into the bases of the intestinal glands. Unlike most species, in the rabbit two distinct cell types are present within the tubules. Serous cells, which occur in small groups in the blind endings to the tubules, contain a concentration of ergastoplasm in the basal cytoplasm and the apical cytoplasm is occupied principally by discrete secretory droplets. Intercellular secretory canaliculi occur between opposed serous cells and between serous and mucous cells. The latter cells possess little ergastoplasm but exhibit an extensive development of the Golgi apparatus in the supranuclear region. Secretory droplets are pale and show a tendency to fuse into complexes. No intercellular canaliculi occur between mucous cells.The cytological features are discussed in relation to previous observations on duodenal glands of other species, where only mucous cells are present. It is apparent that there are species differences with regard to mucous cells. These structural differences may reflect physiological and biochemical differences in the glands. The significance of the presence of serous cells in rabbit duodenal glands is unknown.