The influence of photoperiod and melatonin on testis size, body weight, and pelage colour in the Djungarian hamster (Phodopus sungorus)

摘要: The responses of testes, body weight, and pelage colour to short long photoperiods in winter were determined adult male hamsters with without the implantation melatonin. Animals condition, involuted testes pelage, kept at 20 °C under conditions either (16 h per day) or (8 beginning on 2 January. In each condition one group was implanted three times weekly intervals melatonin beeswax, a control beeswax only, another left untreated. A further remained natural day light. After 37 days groups had reached summer while treated delayed testicular development, closely resembled both shortday daylight (Fig. 2–4). there no difference between two groups. All showed some testis development as compared animals killed experiment. Hamsters marked annual cycle weight which paralleled gonadal activity 5). experimental corresponding increase paralleling 6). significantly higher than all other groups, significant differences melatonin, short-day daylight. Testis size end experiment highly correlated 7, Table 1).