Functional regulation of testosterone underlying state transition in seasonal spermatogenesis of Plateau Pika (Ochotona curzoniae).

This article investigates the role of testosterone in regulating seasonal spermatogenesis in male Plateau Pikas (Ochotona curzoniae), a long-day breeding mammal native to the Qinghai–Tibetan Plateau. The study demonstrates that testosterone levels fluctuate seasonally, correlating with changes in testicular development and germ cell populations, and that testosterone promotes spermatogonial proliferation and differentiation while its inhibition induces germ cell apoptosis. Transcriptomic analyses reveal that testosterone influences gene expression related to androgen receptor signaling and retinoic acid pathways, which are critical for spermatogonial fate determination. These findings elucidate the dose-dependent dual role of testosterone in maintaining spermatogonial survival during dormancy and stimulating differentiation during the breeding season, providing new insights into hormonal regulation of seasonal reproduction in mammals.