Release of cytoplasmic apical protrusions from principal cells of the cat epididymis, an electron microscopic study.

Epididymides of captive normal adult cats were studied by light and transmission electron microscopy. Release of apical portions of principal cells occurred by a process of pinching-off. The membrane-bound bodies (spherules) formed were then found in the epididymal lumen. We postulate that this represents an apocrine secretion process. Such phenomenon were present in all segments of the epididymis, whether caput, corpus, or cauda. Rows of microvesicles similar to those described in other species were also observed between microvilli. The mechanism of formation of spherules and microvesicles seemed to be formed by a different mechanism.