An interventional study of Crystalline amino acids to assess myofibrillar protein synthesis rates and Crystalline amino acids to assess whole-body protein turnover, amino acid oxidation, and net protein balance in Healthy Adult Males, sponsored by University of Toronto. Completed at 1 site in Canada. Open to male participants aged 18 Years to 35 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2021-05-14.
Sponsored by University of Toronto · Not applicable, Interventional, and Treatment
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).
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).
University of Toronto is the lead sponsor of 397 studies on the registry; 59 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Subjects receive 0.25g/kg crystalline amino acids modelled after egg protein, enriched with L-\[1-13C\]leucine and L-ring-\[2H5\]phenylalanine with a primed-constant infusion of L-\[555-2H3\]leucine to assess myofibrillar protein synthesis rates
Dietary Supplement: Crystalline amino acids to assess myofibrillar protein synthesis rates
Subjects receive 0.25g/kg crystalline amino acids modelled after egg protein, enriched with L-\[1-13C\]leucine with a primed-constant infusion of L-\[555-2H3\]leucine to whole-body protein turnover, amino acid oxidation, and net protein balance
Dietary Supplement: Crystalline amino acids to assess whole-body protein turnover, amino acid oxidation, and net protein balance
Amino acid dose = 0.25g/kg bodyweight
Amino acid dose = 0.25g/kg bodyweight
Myofibrillar protein synthesis rates
Myofibrillar protein synthesis rates assessed by oral and intravenous tracers during Fast, Fed, and Ex-Fed
Time frame: 5 hours
Whole-body protein turnover
Whole-body protein turnover assessed by oral and intravenous tracers during Fast, Fed, and Ex-Fed
Time frame: 5 hours
Amino acid oxidation and net protein balance
Amino acid oxidation and net protein balance assessed by oral tracers during Fast, Fed, and Ex-Fed. Net protein balance is derived from the difference between amino acid intake (known) and total amino acid oxidation over the 5h measurement period.
Time frame: 5 hours
Muscle anabolic signalling
Immunoblotting for mTORC1/key downstream targets of mTORC1
Time frame: 2 and 5 hours
Amino acid transporter expression
Immunoblotting for amino acid transporters LAT1/SNAT2
Time frame: 2 and 5 hours
Plan to share: No
This study is completed, as verified in May 2021. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
University of Toronto