A Sertoli cell, a subtype of the sustentacular cell, is a "nurse" cell found in the testicles and contributes to the spermatogenesis, or the process of sperm creation.
Testosterone and other androgens are made by Leydig cells. The germ cells are fed by the Sertoli cells.
They create a variety of proteins, including enzymes, hormones, androgen binding proteins, and inhibin.