| First Author | Ukropec J | Year | 2006 |
| Journal | Endocrinology | Volume | 147 |
| Issue | 5 | Pages | 2468-80 |
| PubMed ID | 16469807 | Mgi Jnum | J:129662 |
| Mgi Id | MGI:3769953 | Doi | 10.1210/en.2005-1216 |
| Citation | Ukropec J, et al. (2006) Leptin is required for uncoupling protein-1-independent thermogenesis during cold stress. Endocrinology 147(5):2468-80 |
| abstractText | We investigated the role of leptin in regulating energy metabolism through induction of uncoupling protein (UCP)-1-based brown fat thermogenesis by comparing phenotypes of energy balance in ob/ob and double-mutant ob/ob.Ucp1(-/-) mice. Measurements of adiposity and lean body mass (nuclear magnetic resonance), energy expenditure (indirect calorimetry), body weight, food intake, and core body temperature were determined in the two mutant stocks of 3-month-old mice maintained at an initial ambient temperature of 28 C for 21 d and then at 21 C for 16 d, and finally with leptin administration for 8 d at 21 C. No phenotypic differences between ob/ob and ob/ob.Ucp1(-/-) mice were detected, suggesting that UCP1-based thermogenesis is not essential for the regulation of adiposity in ob/ob mice at temperatures between 21 and 28 C. Although both Ucp1(-/-) and ob/ob mice can survive in extreme cold at 4 C, provided they are adapted to the cold by gradually lowering ambient temperature, ob/ob.Ucp1(-/-) mice could not adapt and survive at temperatures lower than 12 C unless they were administered leptin. As the ambient temperature was reduced from 20 to 16 C, ob/ob.Ucp1(-/-) mice treated with leptin have elevated levels of circulating T(3) that correlate with elevated sarcoendoplasmic reticulum Ca(2+) ATPase 2a mRNA levels in gastrocnemius muscle. Furthermore, ob/ob.Ucp1(-/-) mice, treated with T(3), were able to maintain body temperature and stimulate sarcoendoplasmic reticulum Ca(2+) ATPase 2a expression when the ambient temperature was gradually reduced to 4 C. Thus, in the absence of UCP1, leptin-induced thermogenesis protects body temperature in part through its action on the thyroid hormone axis. |
