Patho-Physiological Observations of Sertoli Cells in Patients with Germinal Aplasia or Severe Germ Cell Depletion. Ultrastructural Findings and Hormone Levels1

The purpose of this study was to examine the fine structure of Sertoli cells in patients with a severe or complete depletion of germ cells. In normal seminiferous tubules Sertoli cells are characterized by a cytoplasm rich in the common cellular organelles, particularly smooth endoplasmic reticulum and mitochondria. Lipid droplets, Golgi, rough endoplasmic reticulum, dense granules, annulate lamellae and crystals of Charcot-Böttcher are also present, although the latter two structures are not constantly observed. Occluding junctional complexes join adjacent Sertoli cells near the base of the seminiferous epithelium. In patients exhibiting germinal aplasia or severe germ cell depletion there are three morphological features of the Sertoli cells which stand out: 1) A marked increase in the number of fine filaments in the basal portion of the Sertoli cell cytoplasm. In some of these regions few other organelles are present; 2) Extensive junctional complexes between neighboring Sertoli cells extending from the base of the tubule to the lumen; and 3) Elaborate interdigitations between the plasma membrane of adjacent Sertoli cells. In addition to these special features, many areas of Sertoli cells in germinal aplasia show the common organelles found in normal humans. It has previously been assumed that Sertoli cells are normal in patients with germinal aplasia, but the present ultrastructural study demonstrates that they possess certain morphological abnormalities. These observations are consistent with the conjecture that in patients with severe germ cell depletion the increase in plasma FSH may be due to impaired Sertoli cell function resulting in diminished feedback inhibition of gonadotropin release.