Dual control of seasonal time keeping in male and female juvenile European hamsters.

摘要: In contrast to photoperiodic rodent species, adult circannual European hamsters (Cricetus cricetus) do not rely on melatonin as transducer of the message. Instead, seasonal entrainment involves a special circadian organisation which characterizes photoperiod-sensitive phase. When days shorten precise activity pattern ("summer pattern") switches weak or arrhythmic "winter pattern". At very same day gonadal regression is initiated and clock reset. this difference in time measurement, broad span offspring are born birth-season dependent timing puberty similar rodents. We investigated how juvenile measure photoperiod situate themselves at proper position annual cycle. Activity 6-sulphatoxymelatonin (aMT6s) excretion were recorded pups five litters different seasons. Pups all showed an identical with adults' summer until postnatal 78, suggesting that pathway known reset adults functional. The synchronous start reproduction yearlings supports this. However, since occurred before switch pattern, birth year must be controlled by other means. As species might involved, aMT6s daily rhythms from early life on.