Evaluation of Stable Isotope Labeling Technique in Measuring the Tissues' Protein Fractional Synthesis Rates in Rats

摘要

Aims: The objective of this study was to evaluate the technique for measuring tissues' protein fractional synthesis rates with [L-N-15] Leucine. Materials and methods: Sixty male Sprague-Dawley rats were randomly assigned to different groups. After intravenous injection with [L-N-15] Leucine, the enrichment of N-15 in different time intervals was measured with the same dosage and at the same time by variable dosage. Results: During the period from 0 to 30 minutes, there was nearly a linear increase in enrichment of N-15 in both the free amino acid pool and the bond amino acid pool in rats' tissues, and the peak was achieved at 30 minutes. With the increase of dosage, the fractional synthesis rates rose. However, when the dosage was more than 1.0 mmol/kg, there was no significant discrepancy. Conclusions: For measuring the tissues' protein fractional synthesis rates with [L-N-15] Leucine in rats, 30 minutes post-injection is optimal, and 1.0 mmol/kg is the most suitable dosage.