In the mammalian testis, the Sertoli cell plays a key role in the development and maintenance of spermatogenesis. Indeed, within the seminiferous tubule, the structure of the Sertoli cells and the specialized junctions between them and the neighbouring germ cells, contribute to create the sophisticated microenvironment and to bring all the nutriments require for a full development of germ cells. In this review, we have compared the main Sertoli cell functions in the rat and the pig to the available data concerning the human. We have included our recent results obtained from testicular tissues of 15 young men (mean age: 29 years) from which we have prepared the Sertoli cells. In addition to the lactate and estradiol-17 beta syntheses, the human Sertoli cell produces several proteins, namely transferrin, ferritin and inhibin under the control of germ cells.