Sertoli cell-specific expression of rat androgen-binding protein in transgenic mice: effects on somatic cell lineages

The Sertoli cells of many species produce an androgen binding protein (ABP) which carries testicular androgens to the epididymis and is thought to play a role in sperm maturation. In the present report we analyzed the morphological modifications present in Leydig, Sertoli, and peritubular cells of the testis of young adult male mice transgenic for ABP gene, which overproduce ABP in testis. By in situ hybridization we demonstrated that ABP is specifically produced by Sertoli cells. Using light and electron microscopy, we detected scattered alterations of the seminiferous tubule cells which include cell degeneration and vacuolization. Leydig and Sertoli cells present morphological signs of hyperfunctioning compensatory mechanisms which include increased amounts of lipid droplets probably due to the existence of a stimulated steroid synthesis that in turn could be a consequence of the decreased unbound testosterone and/or a direct paracrine effect of ABP. Peritubular cells also present numerous signs of hyperstimulation.