Abnormal biopterin metabolism is a major cause of impaired endothelium-dependent relaxation through nitric oxide/O2-imbalance in insulin-resistant rat aorta. - Shinozaki,K.; Kashiwagi,A.; Nishio,Y.; Okamura,T.; Yoshida,Y.; Masada,M.; Toda,N.; Kikkawa,R. (Diabetes, 1999)