FIG. 1.

IRS-1 KO preadipocytes show impaired differentiation. Brown adipose precursor cells isolated from newborn wild-type (WT) and IRS-1 KO (KO) mice were grown to confluence. At confluence (day 0), differentiation was induced as described in Materials and Methods. At the indicated days, cells were stained with oil red O (A) or prepared for Northern blot (B) and Western blot (C) analysis of various adipogenic markers, as shown. Results are representative of at least two independent experiments.