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Low temperature stimulates pineal activity in Syrian hamsters
Author(s) -
Stokkan KarlAme,
aka Keico O.,
Lerchl Alexander,
Vaughan Mary K.,
Reiter Russel J.
Publication year - 1991
Publication title -
journal of pineal research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 131
eISSN - 1600-079X
pISSN - 0742-3098
DOI - 10.1111/j.1600-079x.1991.tb00008.x
Subject(s) - melatonin , endocrinology , medicine , syrian hamsters , circadian rhythm , pineal gland , biology , hamster , brown adipose tissue , diel vertical migration , period (music) , nocturnal , photoperiodism , adipose tissue , ecology , physics , acoustics
Stokkan K‐A, Nonaka KO, Lerchl A, Vaughan MK, Reiter RJ. Low temperature stimulates pineal activity in Syrian hamsters. J Pineal Res 1991 : 10:4348. Abstract: The effect of 24‐hr exposure to cold (5°C) was studied in male Syrian hamsters adapted to short days (LD 8:16). Both pineal N‐acetyltransferase (NAT) activity and pineal and serum concentrations of melatonin showed a clear, diel rhythm with a moderate but significant increase late in the dark period. The nighttime peak levels of NAT activity and pineal and serum melatonin were significantly higher in the animals that had been exposed to cold than in those remaining in warm (22°C) conditions. The activity of type‐II 5'‐deiodinase (5'D) in the brown adipose tissue (BAT) was not different after 24 hr of cold exposure between cold‐ and warm‐exposed hamsters, and the enzyme did not show any diel rhythmicity. It has been speculated that some effects of cold exposure may be simulated by melatonin treatment; the present data further support this notion. The apparent lack of response in BAT 5'D activity remains enigmatic and needs further investigation.