Brown adipose tissue thermogenesis and the energetics of lactation in rodents.

Brown adipose tissue thermogenesis has been shown to be suppressed during lactation in rats and mice. In parallel with this suppression there is a reduction in the capacity for non-shivering thermogenesis in the whole animal. The extent to which thermogenesis is reduced in lactation is related to litter size, the larger the litter the greater being the reduction. It is argued that the suppression of brown adipose tissue thermogenesis during lactation results in a substantial economy in the non-lactational component of maternal energy expenditure.