Development of Oral Amino Acid Tracers to Study Protein Turnover in Humans

Healthy Adult Males Clinical Trial

Official title: Development of Oral Amino Acid Tracers to Study Protein Turnover in Humans

Status Completed

Clinical Trial Summary

Previous studies have used a combination of oral L-[1-13C]leucine and intravenous labeled L-[5,5,5-2H3]leucine to assess the acute postprandial changes in whole-body protein turnover (12, 19). Intravenous and dietary-labeled amino acid tracers have also been used in tandem to assess rates of myofibrillar protein synthesis in response to bolus protein ingestion and resistance exercise (46). By validating whole-body net balance to myofibrillar protein synthesis, our proposed multi-tracer approach will develop minimally invasive models to study protein turnover in a variety of populations in which traditional infusions and/or repeated blood samples are not possible (i.e. pediatric, free-living populations).

Clinical Trial Description

The primary objective of the proposed study is to validate the use of a novel oral tracer model to accurately and reliably measure myofibrillar protein synthesis. It is hypothesized that oral L-[1-13C]leucine and L-[ring-2H5]phenylalanine, ingested as a bolus to mimic an intravenous 'pulse dose' administration (51, 65), will reveal similar rates of myofibrillar protein synthesis when compared to traditional intravenous L-[5,5,5-2H3]leucine infusion. Moreover, it is hypothesized that both methods will reveal the expected graded changes in myofibrillar protein synthesis in response to feeding and resistance exercise (i.e. fasted<feeding<exercise & feeding). The secondary objective of the proposed study is to develop and validate non-invasive models to measure whole-body amino acid oxidation and net balance in response to feeding and resistance exercise. It is hypothesized that whole-body net balance, as determined by a novel oral tracer model (i.e. L-[1-13C]leucine) , will align with traditional intravenous tracer methodology (i.e. L-[5,5,5-2H3]leucine) and reveal the expected physiological changes in whole-body protein turnover in response to feeding and resistance exercise (i.e. fasted<feeding<exercise & feeding). ;

Related Conditions & MeSH terms

• Healthy Adult Males

• NCT number: NCT04887727
• Study type: Interventional
• Source: University of Toronto
• Status: Completed
• Phase: N/A
• Start date: February 25, 2019
• Completion date: August 31, 2019