Final answer:
Sertoli cells, or testicular nurse cells, support spermatogenesis by creating a blood-testis barrier, supporting meiosis, and concentrating testosterone, but they do not secrete Müllerian inhibiting factor nor progesterone-binding protein.
Step-by-step explanation:
The testicular nurse cells, also known as Sertoli cells, are vital for the process of spermatogenesis, the production of sperm. These cells perform numerous functions such as creating a blood-testis barrier, supporting meiosis, coordinating spermiogenesis, and secreting signaling molecules that promote sperm production. Contrary to the potential options provided, Sertoli cells do not secrete Müllerian inhibiting factor; this is secreted by fetal testes to prevent the development of female reproductive structures. They do not secrete progesterone-binding protein either. They are also associated with concentrating testosterone, which is essential for maintaining the spermatogenesis process, and they phagocytize excess cytoplasm during sperm cell development.