Abstract:

Based on the data reported in literature and the previous experience, the molecular mechanism of mammalian circadian clock system and the research progress of testicular circadian clock within the past two decades are summarized, and the evidence of the presenceof the testicular circadian clock in mammals is put forward. Afterwards, a series of important reproductive physiological processes regulated by mammalian testicular circadian clock are elaborated, such as testosterone synthesis and spermatogenesis. Moreover, other important factors affecting mammalian testicular clock, such as aging, stress, and harmful chemicals, are also briefly listed. In addition,

the current studies on the molecular mechanism of testicular circadian clock maintenance, its regulation of other reproductive accessory

cells physiological functions and spermatogenesis within specific periods, and the construction of tissue-specific and conditional knockoutmouse models are analyzed. This article advances our understanding on how to find the target sites to increase testosterone levels and sperm motility, and effectively improve the reproductive potential of male breeding animals from the perspective of testicular circadian clock.

Key words: testis, circadian clock gene, reproduction, testosterone synthesis, spermatogenesis