Nikkei ended slightly lower on Friday as investors refrained from active buying on caution over market overheating. The 225-issue Nikkei Stock Average closed down 24.97 points, or 0.17 percent, from Thursday at 14,561.54. The broader Topix index of all First Section issues on the Tokyo Stock Exchange was down 0.73 point, or 0.06 percent, at 1, 205.52. Decliners were led by insurance, tire and air transport companies, while gainers included sea transport, real estate and metal products issues. The turnover was about 1,607.8 billion yen (16.39 billion U.S. dollars).