Changes in the volume of Sertoli cells during the cycle of the seminiferous epithelium in the rat.

Volume density of Sertoli cells in mature rats was estimated in different stages of the cycle of the seminiferous epithelium. Manual point-counting on electron micrograph montages revealed a more than 40% increase in Sertoli cell volume from just before to just after spermiation. It is suggested that this variation should be considered in studies of stage-dependent cyclic variations in activity of Sertoli cells and/or germ cells.