[Testicular tissue homotransplantation of newborn rat: experimental study].

32 newborn Sprague-Dawley rats were used as donors and 32 castrated male out-bred mature rats as recipients. The pieces of testes tissue were implanted subcutaneously in the bilateral hind legs. Two month follow-up showed that the grafts survived and increased in size. Serum testosterone levels of the recipients were higher than those of the castrated. They peaked and were close to the levels of the mature rats even 45 days after the implantation. Serum FSH, and, LH levels in the recipients were lower than those of the castrated. The mechanism of the newborn testes as an immuno-privileged donor is discussed.