The fine structure of Brunner's glands in the rat

AbstractThe appearance of Brunner's glands in the rat, before and after feeding, has been examined with the electron microscope. The glands are arranged in the duodenal submucosa in aggregates of coiled tubules which open into the bases of the crypts of Lieberkühn. Component cells appear to be more mucous than serous. The basal cytoplasm contains some granular endoplasmic reticulum, numerous free ribosomes and mitochondria. Multiple Golgi elements lie in relation to the nucleus and the apical cytoplasm contains varying concentrations of pale secretory droplets which show a tendency to fuse into complexes. Scattered between the large secretory droplets are numerous small vesicles, also considered to contain a secretory product.The cytological features are discussed in relation to previous observations on Brunner's glands in other species. It is apparent that there are considerable species differences. However, in all species it appears likely that the complex secretory materials are elaborated principally by the ergastoplasm.