Role of brown adipose tissue in body temperature control during the earlypostnatal period in Syrian hamsters and mice

摘要

Brown adipose tissue (BAT) contributes to non-shivering thermogenesis and plays animportant role in body temperature control. The contribution of BAT thermogenesis to bodytemperature control in a non-cold environment was evaluated using developing hamsters.Immunostaining for uncoupling protein 1 (UCP1), a mitochondrial protein responsible forBAT thermogenesis, indicated that interscapular fat tissue had matured as BAT at day 14.When pups were placed on a thermal plate kept at 23°C, the body surface temperaturedecreased in day 7- and 10-day-old pups but was maintained at least for 15 min in14-day-old pups, indicating that hamsters are unable to maintain their body temperatureuntil around day 14 even in a non-cold environment. Body temperature maintenance was alsoevaluated in UCP1-deficient mice. BAT analysis showed that the UCP1 protein level in Hetero mice was 61.3 ± 1.4% of that in wild-type(WT) mice and was undetected in knockout (KO) mice.When 12-day-old pups were place on a thermal plate at 23°C, body surface temperature wasmaintained for at least 15 min in WT and Hetero mice but gradually dropped by 2.4 ± 0.2°Cin 15 min in KO mice. It is concluded that BAT thermogenesis is indispensable for bodytemperature maintenance in pups of hamsters and mice, even in the non-cold circumstances.The early life poikilothermy and the later acquirement of homeothermy in hamsters may bebecause of the postnatal development of BAT.