Effects of a chronic treatment with testosterone on the morphology of the interstitial cells of the rat testis: an ultrastructural stereologic study.

The suppressive effects of chronic testosterone administration on the rat testicular interstitial cells (Leydig cells) were investigated by stereological methods. The volume of cells, nuclei, mitochondrial compartment and smooth endoplasmic reticulum (SER), as well as the surface area of SER and mitochondrial cristae decreased significantly as a function of the duration of treatment. The decrease in the SER volume accounted for about 75-80% of that in the cell volume. These findings lend support to the view that SER is the subcellular organelle more responsive to the changes in the functional activity of rat Leydig cells.