Serum branched-chain amino acids in the diagnosis of hyperinsulinism in infancy.
Fasting values of branched-chain amino acids (valine, leucine, and isoleucine) were measured by column chromatography in the sera of 27 normal infants and children, 15 days to 9 years of age, 14 children with documented ketotic hypoglycemia one to 7 years of age, and in 14 sera from six infants, 15 days to 2 years of age, with documented hyperinsulinism. In normal children and those with ketotic hypoglycemia, each individual branched-chain amino acid and their sum were significantly negatively correlated with blood sugar values ranging between 11 and 92 mg/dl (P < 0.001). In infants with hyperinsulinism, branched-chain amino acid concentrations were significantly lower (P < 0.001) without correlation with blood sugar values ranging between 13 and 51 mg/dl, and plasma insulin concentrations (9 to 85 microU/ML). In all the children the sum of branched-chain amino acids was positively correlated with blood beta OH butyrate concentrations measured at the same time (r = 0.75, P < 0.001). The association of low blood sugar and low branched-chain amino acid concentrations during fasting seems characteristic of hyperinsulinism, and the measurement of branched-chain amino acids in these infants offers a physiologic indicator of the diagnosis of hyperinsulinism.
D000597:Amino Acids, Branched-Chain / Q000097:blood*; D001786:Blood Glucose / Q000032:analysis; D002675:Child, Preschool; D005215:Fasting; D006801:Humans; D006885:Hydroxybutyrates / Q000097:blood; D006946:Hyperinsulinism / Q000097:blood*; D007003:Hypoglycemia / Q000097:blood*; D007223:Infant; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000097:blood*; D007328:Insulin / Q000097:blood
D000597:Amino Acids, Branched-Chain; D001786:Blood Glucose; D006885:Hydroxybutyrates; D007328:Insulin