The problem of the present invention is to provide a compound useful for the prophylaxis or treatment of diseases related to the control of the differentiation of muscle cell or adipocyte differentiation, such as diabetes, obesity, dyslipidemia, and having a superior efficacy. The present invention provides an agent for the prophylaxis or treatment of diabetes, obesity or dyslipidemia, containing a compound represented by the formula (I) wherein each symbol is as defined in the DESCRIPTION, or a salt thereof or a prodrug thereof.
