Text Box: PLASMA LEVELS OF BIG ENDOTHELIN-1, ENDOTHELIN-1 AND SUBSTANCE P IN INFANTS AND CHILDREN WITH CONGESTIVE HEART FAILURE Wu JR1, Yeh JL2, Dai ZK1, Hsu JH1 Departments of Pediatrics1 and Pharmacology2, Kaohsiung Medical University, Kaohsiung, Chinese Taipei Objective: To characterize the changes in circulating big endothelin-1, endothelin-1, atrial natriuretic peptide (ANP), substance P levels for children with varying degrees of congestive heart failure (CHF). Methods: Plasma neurohormone levels were measured, by using radioimmunoassay, in 81 subjects including 13 normal children (Group A) and 68 with congenital heart disease patients. The plasma norepinephrine and epinephrine levels were measured by high performance liquid chromatography. Results: In patients with CHF (Group D; n=27), big endothelin-1 and endothelin-1 concentrations were markedly elevated as compared with healthy control subjects (n=13) (29.5¡À1.6 vs 18.1¡À2.1 pg/ml; 17.9¡À1.7 vs 7.8¡À1.7 pg/ml, p<0.05). Compared with the controls, the big endothelin-1 levels in the mild (n=15), moderate (n=6) and severe (n=6) CHF subgroup increased by 1.47-, 1.67- and 1.92-folds, respectively. Compared with the controls, the endothelin-1 levels in the mild, moderate and severe CHF subgroup increased by 2.19-, 2.07- and 2.81-folds, respectively. Plasma ANP levels in 27 patients with CHF were significantly higher than those in the 41 patients without CHF (35.5¡À4.2 vs 7.6¡À0.6 pg/ml, p<0.05). Plasma norepinephrine levels in the patients with CHF were significantly higher than those in the patients without CHF (505.6¡À65.6 vs 230.0¡À8.0 pg/ml, p<0.05). Conclusion: A highly significant associated was found between the level of plasma norepinephrine and severity of CHF symptoms. The epinephrine concentration did not significantly vary among the groups. Our results support the idea that changes in big endothelin-1, endothelin-1, ANP, and norepinephrine levels occur concurrently with the presence and severity of heart failure in children. 1982