Transglutaminase immunoreactivity in the male genital tract of the rat.

The distribution of transglutaminase immunoreactivity in the male genital system of the rat has been studied at the light and electron microscopic levels using a highly specific polyclonal antibody. The antibody is obviously secreted in an apocrine fashion in the dorsal prostate as well as the coagulating gland. This moiety is responsible for semen clotting. In addition to the secretory moiety, epididymal sperm contain endogenous immunoreactive material in the cytoplasmic droplet. Whether this is added to the sperm within the epididymis--as is the immunoreactive material on the sperm head--or already present in developing sperm has to be elucidated by further immunoelectron microscopic studies.