Leukemia inhibitory factor reduces body fat mass in ovariectomized mice.

OBJECTIVE Ovariectomized (OVX) mice are known to gain body fat while exposure to estrogens decreases fat mass. We have previously shown that estrogen replacement therapy enhances the expression of receptors for the cytokine, leukemia inhibitory factor (LIF). LIF and other cytokines acting via the gp130 signal transducing receptor have been reported to decrease obesity. In the present study, we investigated whether LIF treatment can reduce obesity in OVX mice. DESIGN Eight-week-old female C57Bl/6 mice were OVX or sham-operated. The mice were treated with LIF, 30 microg/kg or PBS via daily i.p. injections for 15 days (n = 9-10). METHODS Dual X-ray absorptiometry and computerized tomography. RESULTS We found that LIF treatment of OVX mice caused a significant reduction in the weight of white fat depots (P = 0.017) and serum leptin levels (P = 0.011). LIF also caused a significant decrease in brown fat mass (P = 0.036). Treatment with LIF decreased thymus weight but did not affect crown-rump length, femur length, trabecular bone mineral density or the weight of several non-fat organs including the uterus. CONCLUSION The cytokine, LIF, decreases body fat mass in OVX mice, suggesting that estrogen signaling is not required for this effect.