Evaluation of the seminiferous epithelial cycle, spermatogonial kinetics and niche in donkeys (Equus asinus).

Kinetics of spermatogonia as well as localization in niches have been described in rodents, but rarely in large animals or in species of economical interest. In this regard, and envisioning the possibility of spermatogonial transplantation from donkeys (Equus asinus) to mules (Equus mulus mulus), many variables that may contribute for an enhanced understanding of the spermatogonial biology in donkeys were investigated. Testes from five adult donkeys were routinely processed for high-resolution light microscopy.

Genetic factors contributing to defective spermatogonial differentiation in juvenile spermatogonial depletion (Utp14bjsd) mice.

Male mice that are homozygous for the juvenile spermatogonial depletion (jsd) mutation in the Utp14b gene undergo several waves of spermatogenesis. However, spermatogonial differentiation ceases and in adults, spermatogonia are the only germ cells that remain. To understand further the blockage in spermatogonial differentiation in Utp14b(jsd) mutant mice, we correlated the rate and severity of spermatogonial depletion and the restoration of spermatogenesis following the suppression of testosterone or elevation of testicular temperature with the genetic background.