The effects on the proximal caput epididymidis of efferent ductule ligation were studied. After 6 h there was a slight increase in autophagocytosis in the initial segment proper (1A). After 12 h this segment showed cell death and cytoplasmic regression and after 24 h large amounts of necrotic cells and focal degeneration in the epithelium, and desquamated cells and débris in the lumen. After 48 h the epithelium was lower, but degeneration less obvious. Segments 1B, 1C and 2 showed marked cell death and cytoplasmic degeneration. This was more evident after 3 days, especially in 1B. After 5 and 7 days some degeneration was still seen, but essentially regional differences had disappeared, leaving a lower, inactive epithelium throughout. Except for an increase in glycogen granules in segment 1C after 48 h, marked focal degeneration always appeared before general cytoplasmic alterations. Sham operation produced no changes. The regression might be caused by the cut supply of androgen binding protein or a growth factor in rete testis fluid.

No abstract

The differentiation of rat seminiferous tubules have been studied in 13 to 19 days old. Testicular weight and tubular cross-sectional area were more than doubled during this period. The percentage of tubules with more than 10 primary spermatocytes increased from 4% to 90%, and the lanthanum excluding ability of the inter-Sertoli cell junctions (the blood-testis barrier) showed a similar increase but two days later. ABP production in vitro increased more than twentyfold from day 13 to day 19 of age. It is concluded that the differentiation of Sertoli cell function and the appearance of primary spermatocytes are temporally correlated which supports the assumption that the function of the Sertoli cells is important for initiation and maintenance of spermatogenesis.

The ultrastructure of Sertoli-Sertoli and Sertoli-germ cell surface specializations in the domestic fowl was studied in material fixed by vascular perfusion through the thoracic aorta. Three main types of surface specializations were found between adjacent Sertoli cells. These are focal tight junctions, desmosome-like devices, and a specialization characterized by the presence of long and dilated subsurface cisternae of rough endoplasmic reticulum. Typical inter-Sertoli cell junctions similar to those of mammals were absent. Germ cells were attached to Sertoli cells mainly by desmosome-like devices of varying appearance. The junctions between Sertoli cells and elongating or elongated spermatids, "the mantle", consisted of only slight condensations of filamentous material in the Sertoli cell. The tight junctions between adjacent Sertoli cells were efficient in preventing lanthanum from passing towards the lumen beyond the level of the spermatogonia.