Ultrastructure of the rete testis in the cat (Felis domestica, L.).

The rete testis (RT) in the cat comprises three distinct and sequential parts: septal or adlobular; mediastinal and tunical parts. This last part is followed by the small extratesticular rete testis. The whole of the RT tubules and/or channels is lined by single low columnar and/or cuboidal epithelium with ultrastructural peculiarities of secretory and absorptive functions. The Golgi apparatus polarity (cis-trans surfaces), its relation with the long profiles of the ER, mainly with the rough ER, and presence of apical uncoated electrodense granules are suggestive of active release of macromolecules, probably glycoproteins. The absorptive function is proposed through the observation of a conspicuous microvacuolar-vesicular apical complex in epithelial cells. Moreover spermatozoa phagocytosis is also noticed, mainly in the septal part of the RT.