Leptin promotes the fat preference associated with low-temperature acclimation in mice

ABSTRACT

Although fluctuations in energy metabolism are known to influence intake as well as nutrient selection, there are no definitive reports on how food preferences change with changes in habitat temperature. We investigated the effects of habitat temperature on appetite and food preference and elucidated the underlying mechanism by conducting a feeding experiment and a leptin administration test on mice reared at low temperatures. Our results showed that the increased food intake and HFD preference observed in the 10°C group were induced by decrease in plasma leptin concentration. Then, a leptin administration experiment was conducted to clarify the relationship between leptin and food preference with low-temperature acclimation. The control group reared in 10°C significantly preferred the HFD, but the leptin-administered group did not. These results show that the peripheral system appetite-regulating hormone leptin not only acts to suppress appetite but also might inhibit preference for lipids in low-temperature acclimation.     

A new decalcifying technique for immunohistochemical studies of calcified tissue, especially applicable to cell surface marker demonstration

We have developed a new decalcifying technique for use in light and electron microscopy studies utilizing immunohistochemical staining of calcified tissues. Specimens containing calcified tissues can be adequately decalcified at a pH of 7.1-7.4 and temperature of -5 degrees C, without freezing, by use of a solution containing EDTA, sodium hydroxide, and glycerol. In this study, Leu-2a, Leu-3a, Leu-4, Leu-7, Leu-12, Leu-14, Leu-M1, Leu-M2, Leu-M3, and HLA-DR-positive cells in destructive lesions of bone tissues from patients with rheumatoid arthritis and osteomyelitis were successfully detected immunohistochemically. Furthermore, the presence of HLA-DR antigen on the surface of the infiltrating cells in the same lesions could be demonstrated using the immunoelectron microscopic technique. The results reported here have not previously been obtainable using conventional decalcifying techniques.