Amino Acids as Substrates in Children with Growth Hormone Deficiency and Hypoglycemia

[摘要] In order to investigate the role of amino acid (AA) substrates in the hypoglycemia associated with human growth hormone (hGH) deficiency, we measured 12-hour fasting blood glucose and total quantitative AA concentrations in 11 children with hGH deficiency during three study periods: (1) before hGH replacement; (2) after 12 months of hGH treatment; and (3) after discontinuation of hGH for three months. The results were compared to studies in 16 control subjects. Fasting blood glucose concentrations were significantly ( P < .05) lower in the hGH-deficient children prior to hGH treatment as compared to the control subjects (67.0 ± 5.3 vs 80.7 ± 5.3 mg/100 ml, X ± SE). Fasting total serum AA concentrations were similar in the patients and in the control subjects; however, after 12 months of hGH replacement, there was a significant ( P < .01) elevation of serum AA (2,750 ± 170 vs 2,283 µmoles/liter). Fasting serum concentrations of alanine, glycine, arginine, and tryptophan were also significantly elevated ( P < .01) with hGH treatment; ornithine, tyrosine, lysine, methionine, and phenylalanine showed lesser elevations ( P < .05), whereas threonine decreased significantly ( P < .01). The fasting hypoglycemia seen with isolated hGH deficiency is not an AA substrate-limited disorder. The finding of increased concentrations of AA with hGH replacement suggests increased retention of nitrogen and synthesis of AA or a decreased requirement of AA for gluconeogenesis due to availability of other substrates.

[学科分类] 儿科学