Further observations on the Sertoli cell junctions of the mouse testis after metal contract freeze-fracture, and comparisons with cellular junctions of other epithelial cells.

Using a metal contact freezing methods, the junctional complexes of Sertoli cells and other epithelial cells (intestine, liver, and epididymis) in the mouse were studied by freeze-fracture in unfixed and in aldehyde-fixed specimens. The tight junctions of the Sertoli cells without fixation consists of discrete rows of particles located preferentially on the E face. Continuous furrows with or without tight-junctional particles are found on both fractured faces. The majority of the tight-junctional particles of th Sertoli cells are situated at one side of the furrow rather than in the center. The "aisle" configuration of the gap junction is seen in developing Sertoli cells prepared without fixation. Tight junctions of epithelial cells other than Sertoli cells consists of discrete rows of particles on the E face and furrows on the P face when prepared without fixation. The tight and gap junctions of the Sertoli cells are not affected by fixation, but the tight junctions of other types of epithelial cells are effected as previously suggested. A distribution pattern of the gap-junctional particles of the Sertoli cells and of other cells shows a pleomorphism. Changes in gap junctions produced by fixation could not be detected clearly. Characteristics of the Sertoli-cell junctions are discussed. Desmosomes between the intestinal epithelial cells without fixation are presented.