Reproductive Response of Adult Siberian Hamsters to One-Hour Melatonin Infusions

[摘要] The pineal hormone melatonin is known to play an important role in mediating photoperiodic messages to the reproductive system in seasonal breeding animals. In this study, we investigated whether a 1 h subcutaneous infusion of 50 ng of melatonin at 2000-2100 hours, effective in causing inhibition of testicular development in the juvenile Siberian hamsters (Phodopus sungorus), would cause testicular regression in adults of this species housed on a long photoperiod (LD16:8).Pinealectomized adult hamsters received programmed subcutaneous infusions of 50 or 500 ng of melatonin or vehicle (0.12 ml) at 2000-2100 hours each day for 8 weeks.We found that the testicular weights of infused animals receiving melatonin or vehicle were not different from each other; all animals retained large testes.These results show that a 50 ng melatonin infusion at a particular time point (2000-2100 hours) is not effective in altering the functional status (size) of the testes of adults.

[学科分类] 生物科学（综合）

[关键词] Melatonin;Siberian hamster;Photoperiod;Testes;Infusion