title: Photoperiod and temperature effects on adrenal tyrosine hydroxylase and its relation to nonshivering thermogenesis.
abstract: Exposure to short photoperiod increased the activity of adrenal tyrosine hydroxylase (TOH). During summer, the shortening of photoperiod at constant Ta of 23 degrees C stimulated TOH from 7.28 to 10.94 nmoles L-Dopa (h . pair of adrenals), which was as effective as a chronic exposure to 15 degrees C Ta, elevating TOH to 9.1 nmoles L-Dopa/(h . pair of adrenals). The stimulation of TOH by photoperiod or cold exposure in Djungarian hamsters was well correlated with an increase in their ability for nonshivering thermogenesis.
mesh_terms: D000311:Adrenal Glands / Q000378:metabolism*; D000818:Animals; D001833:Body Temperature Regulation; D001835:Body Weight; D002395:Catecholamines / Q000096:biosynthesis; D003080:Cold Temperature; D006224:Cricetinae; D006358:Hot Temperature; D008027:Light; D009929:Organ Size; D012621:Seasons; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*
chemical_list: D002395:Catecholamines; D014446:Tyrosine 3-Monooxygenase