Effects of thyroid hormones and cold acclimation on the energy metabolism of the striped hamster (Cricetulus barabensis).

To examine the effects of low ambient temperature and thyroid hormones on the energy metabolism of the striped hamster (Cricetulus barabensis), adult male striped hamsters were kept at 30 °C, or acclimated to 5 °C, for 4 weeks. During this time, hamsters were treated with a synthetic thyroxine, levothyroxine sodium (LTS), the antithyroid drug methimazole, or saline solution (control). Hamster's food intake, basal metabolic rate (BMR), non-shivering thermogenesis (NST), thyroid hormones, body fat content, mitochondrial state-4 respiration, cytochrome c oxidase, and uncoupling protein 1 (UCP1) gene expression in brown adipose tissue (BAT), were measured.

Sustained energy intake in lactating Swiss mice: a dual modulation process.

Limits to sustained energy intake (SusEI) during lactation are important because they provide an upper boundary below which females must trade off competing physiological activities. To date, SusEI is thought to be limited either by the capacity of the mammary glands to produce milk (the peripheral limitation hypothesis) or by a female's ability to dissipate body heat (the heat dissipation hypothesis). In the present study, we examined the effects of litter size and ambient temperature on a set of physiological, behavioral and morphological indicators of SusEI and reproductive performance in lactating Swiss mice.

Interspecific variation of thermoregulation between small migratory and resident passerines in Wenzhou.

Physiological adaptation arises from several fundamental sources of phenotypic variation. Most analyses of metabolic adaptation in birds have focused on the basal metabolic rate (BMR), the lower limit of avian metabolic heat production. In this study, we investigated thermoregulation in three passerine species; the yellow-billed grosbeak Eophona migratoria, white-rumped munia Lonchura striata and black-throated bushtit Aegithalos concinnus, in Wenzhou, China.