Apparent dissociation between sympathetic activity and brown adipose tissue thermogenesis during pregnancy and lactation in golden hamsters.

Sympathetic activity has been assessed by measurements of noradrenaline turnover in brown adipose tissue and in the heart of golden hamsters during pregnancy and lactation. Noradrenaline turnover was not significantly altered in either tissue in pregnant or lactating hamsters, despite the atrophy of brown adipose tissue that occurs during reproduction. This suggests that sympathetic activity and brown adipose tissue thermogenesis are dissociated during pregnancy and lactation in golden hamsters. The results also indicate that the large increase in food intake lactation does not lead to a diet-induced stimulation of the sympathetic nervous system.