Tokyo stocks ended the morning session slightly lower Friday as investors refrained from active buying amid caution about market overheating. The 225-issue Nikkei Stock Average fell 8.21 points, or 0.06 percent, from Thursday at 14,578.30. The broader Topix index of all First Section issues on the Tokyo Stock Exchange was down 0.66 point, or 0.05 percent, at 1, 205.59. Decliners were led by insurance, tire and steel companies, while gainers included sea transport, real estate and land transport issues.