Leuprolide, a gonadotropin-releasing hormone agonist, enhances colonization after spermatogonial transplantation into mouse testes.

Spermatogonial stem cells can be transplanted from a fertile donor mouse to the testis of an infertile recipient where they establish spermatogenesis and produce spermatozoa. In the present study we investigated whether treatment of recipient mice with the gonadotropin-releasing hormone (GnRH) agonist leuprolide acetate could alter the efficiency of colonization by donor spermatogonial stem cells in the recipient testis. Six recipient mice were treated with busulfan to destroy endogenous spermatogenesis followed by injection of leuprolide acetate to three of the mice. Testis cells from mice carrying the ZFlacZ transgene, which produces beta-galactosidase in spermatids, were used as donor cells for transplantation to allow for identification of donor spermatogenesis in the recipient testis by staining for enzyme activity. The extent of donor cell colonization was compared between leuprolide treated recipients and untreated control mice 3 months after transplantation. Efficiency of colonization by donor cells was markedly enhanced in recipient mice treated with the GnRH agonist leuprolide acetate, which makes the technique of spermatogonial transplantation applicable to a wide range of experimental situations. The present study also indicates that this technique can be used as a biological assay system to investigate factors controlling the establishment and progression of spermatogenesis.