Sammanfattning
Background: Several studies have reported the favorable effect of leucine supplementation on
insulin resistance or insulin sensitivity. However, whether or not leucine supplementation improves
leptin sensitivity remains unclear.
Design: Forty-eight male Sprague-Dawley rats were fed with either a high-fat diet (HFD) or HFD
supplemented with 1.5, 3.0, and 4.5% leucine for 16 weeks. At the end of the experiment, serum leptin
level was measured by ELISA, and leptin receptor (ObR) in the hypothalamus was examined by
immunohistochemistry. The protein expressions of ObR and leptin-signaling pathway in adipose
tissues were detected by western blot.
Results: No significant differences in body weight and food/energy intake existed among the four
groups. Serum leptin levels were significantly lower, and ObR expression in the hypothalamus and
adipose tissues was significantly higher in the three leucine groups than in the control group. These
phenomena suggested that leptin sensitivity was improved in the leucine groups. Furthermore, the
expressions of JAK2 and STAT3 (activated by ObR) were significantly higher, and that of SOCS3
(inhibits leptin signaling) was significantly lower in the three leucine groups than in the control group.
Conclusions: Leucine supplementation improves leptin sensitivity in rats on HFD likely by promoting
leptin signaling.