科研之友
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摘要
Background: Phenylbutyrate is a drug used in patients with urea cycle disorder to elicit alternative pathways for nitrogen disposal. However, phenylbutyrate administration decreases plasma branched-chain amino acid (BCAA) concentrations, and previous research suggests that phenylbutyrate administration may increase leucine oxidation, which would indicate increased protein degradation and net protein loss. Objective: We investigated the effects of phenylbutyrate administration on whole-body protein metabolism, glutamine, leucine, and urea kinetics in healthy and ornithine transcarbamylase-deficient (OTCD) subjects and the possible benefits of BCAA supplementation during phenylbutyrate therapy. Design: Seven healthy control and 7 partial-OTCD subjects received either phenylbutyrate or no treatment in a crossover design. In addition, the partial-OTCD and 3 null-OTCD subjects received phenylbutyrate and phenylbutyrate plus BCAA supplementation. A multitracer protocol was used to determine the whole-body fluxes of urea and amino acids of interest. Results: Phenylbutyrate administration reduced ureagenesis by approximate to 15% without affecting the fluxes of leucine, tyrosine, phenylalanine, or glutamine and the oxidation of leucine or phenylalanine. The transfer of N-15 from glutamine to urea was reduced by 35%. However, a reduction in plasma concentrations of BCAAs due to phenylbutyrate treatment was observed. BCAA supplementation did not alter the respective baseline fluxes. Conclusions: Prolonged phenylbutyrate administration reduced ureagenesis and the transfer of N-15 from glutamine to urea without parallel reductions in glutamine flux and concentration. There were no changes in total-body protein breakdown and amino acid catabolism, which suggests that phenylbutyrate can be used to dispose of nitrogen effectively without adverse effects on body protein economy. Am J Clin Nutr 2011;93:1248-54.
- 出版日期2011-6
