Tyrosine isomers and hormonal signaling: A possible role for the hydroxyl free radical in insulin resistance

Figure 9 The ortho-tyrosine levels of consecutive arterial segments isolated from rats (A). There were significant differences (^aP < 0.05) in the o-Tyr levels among the thoracic aorta (n = 7), abdominal aorta (n = 7), and the femoral artery (n = 9) of rats. The changes in the o-Tyr levels in the consecutive arterial segments of rats after H₂O₂ + AT treatment (i.e., high oxidative state), SOD + CAT treatment (i.e., low oxidative state), and aortic banding were compared with those of the control vessels (B). Control: untreated, control vessels (thoracic: n = 7; abdominal: n = 7; femoral: = 9); H₂O₂ + AT: hydrogen peroxide- and aminotriazole-incubated vessels (aminotriazole is an inhibitor of catalase) (thoracic: n = 5; abdominal: n = 5; femoral: n = 4); SOD + CAT: superoxide dismutase- and catalase-incubated vessels (thoracic: n = 5; abdominal: n = 5; femoral: n = 5); aortic banding (thoracic: n = 5; abdominal: n = 4; femoral: n = 4). Data are the mean ± SEM. The o-Tyr levels are relative to the phenylalanine (Phe) levels (Panels A and B) and are expressed as the percentage of the control vessels (Pane B). ^cP < 0.05; NS, P > 0.05 (ANOVA). Republished with permission of Informa Healthcare from Szijártó et al[19]. o-Tyr: Ortho-tyrosine; NS: Non-significant; SEM: Standard error of the mean.