LOSS OF SPERM IN JUVENILE SPERMATOGONIAL DEPLETION (JS']JSD) MUTANT MICE IS ASCRIBED TO A DEFECT OF INTRATUBULAR ENVIRONMENT TO SUPPORT GERM-CELL DIFFERENTIATION

C57BL/6(B6)-jsd/jsd mice are sterile due to the defective spermatogenesis in the testes. To know the cause of the deficient spermatogenesis in B6-jsd/jsd mice, we examined whether the problem is within or outside the seminiferous tubules by transplanting tubules from cryptorchid testes of B6- +/+ mice into B6-jsd/jsd testes or tubules from B6-jsd/jsd mice into testes of (WB x C57BL/6)F1-W/W(V) (hereafter, WBB6F1-W/W(V)) mice. Type A spermatogonia differentiated into spermatids in seminiferous tubules from cryptorchid testes transplanted into B6-jsd/jsd testes. In contrast, in B6-jsd/jsd tubules transplanted into WBB6F1-W/W(V) testes, type A spermatogonia were stimulated to mitotic proliferation, but didn't proceed to any differentiated germ cells. The present results suggest that the cause of the deficient spermatogenesis in B6-jsd/jsd mice is a defect of intratubular environment to support germ cell differentiation.