This invention provides a method for preparing a
brown adipocyte from a
somatic cell of a
mammal by introducing at least one
brown adipocyte-
related gene or expression product thereof and at least one
reprogramming-
related gene or expression product thereof into the
somatic cell, the
brown adipocyte-
related gene being at least one member selected from the group consisting of PRDM16(P) and C / EBPβ(C), the
reprogramming-related
gene being at least one member selected from the group consisting of Myc family genes (c-Myc(M), N-Myc, L-Myc(L), S-Myc, and B-Myc), GLIS family genes (GLIS1 (G), GLIS 2, and GLIS 3), Klf family genes (KLF1, KLF2, KLF3, KLF4(K), KLF5, KLF6, KLF7, KLF8, KLF9, KLF10, KLF11, KLF12, KLF13, KLF14, KLF15, KLF16, and KLF17), Oct family genes, Sox family genes, and Lin-28.