Pj. Scarpace et al., LEPTIN INCREASES UNCOUPLING PROTEIN EXPRESSION AND ENERGY-EXPENDITURE, American journal of physiology: endocrinology and metabolism, 36(1), 1997, pp. 226-230
In ob/ob mice, leptin increases energy expenditure and sympathetic out
flow to brown adipose tissue (BAT). To test whether the mechanism of i
ncreased energy expenditure may involve increased thermogenesis in BAT
, we acclimated normal rats to thermoneutrality for 2 wk followed by l
eptin administration for 1 wk. Some rats were food restricted for 1 wk
to the level of food consumption in the leptin-treated ad libitum-fed
rats, and the same rats were both food restricted and administered le
ptin for a second week. We examined oxygen consumption and uncoupling
protein (UCP) expression in BAT. Leptin increased oxygen consumption a
fter the 5th and 6th days in ad libitum-fed rats and after the 4th, 5t
h, and 6th days in food-restricted rats. Leptin increased BAT UCP mRNA
levels greater than twofold in both ad libitum-fed and food restricte
d rats. These data demonstrate a leptin-induced increase in energy exp
enditure in nonmutant rodents and suggest that one mechanism by which
leptin increases energy expenditure is through increased thermogenesis
in BAT, including increased expression of UCP.