Effects of Photoperiod and Temperature on Browh Adipose Tissue Thermogenic Properties in Plateau Pika

We examined the effects of temperature and photoperiod on the thermogenic characteristics of brown adipose tissue in plateau pikas (Ochotona curzoniae).Pikas were acclimated in the following groups:1)Long day-warm temperature (16 L:8 D,23 ℃);2)Long day-cold temperature (16 L:8 D,5℃);3)short day-warm temperature (8 L:16 D,23℃);and 4)short day-cold temperature (8 L:16 D,5℃).Both temperature and photoperiod were important environmental cues for changes in thermogenesis for pikas.Low temperature and/or short photoperiod induced increases in tissue protein contents,mitochondrial protein contents of brown adipose tissue,and cytochrome c oxidase activity of brown adipose tissue mitochondria in pika.Animals habitat preference and behavioral properties play an important role in the seasoanl acclimazization of thermogenic characteristics.Our results showed that temperature and photoperiod combined induce thermogenic adjustments in plateau pika.