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Creatine Kinetics, Synthesis From Glycine and Response to Creatine and Amino Acid Supplement in Healthy Humans

This study has been completed.
Information provided by (Responsible Party):
Satish Kalhan, The Cleveland Clinic Identifier:
First received: November 8, 2012
Last updated: January 29, 2014
Last verified: January 2014

The goal of the present study is to quantify the rate of synthesis of creatine in healthy controls and endurance trained subjects. In addition, the effect of oral creatine supplement for seven days on creatine kinetics will be examined.

Ten healthy controls (age 20-35 years) and ten endurance trained subjects will be recruited by advertisement. Endurance trained subjects will be recruited from health clubs. They will be screened for absence of any chronic disease (history, physical examination, CBC, metabolic and liver panel, urinalysis). A DEXA measurement will be done to quantify whole body skeletal muscle mass.

For five (5) days prior to the study, they will be placed on a creatine-free (essentially meat-free) diet. Dietary compliance will be ensured by repeated communication with the subject, by nurse coordinator and the CRU Nutritionist. Subject will maintain daily record of the food intake for validation. On the last day, i.e. 24 hours prior to the tracer study, subject will collect the 24 hours urine sample and bring it to the CRU on the day of the study.

Condition Intervention
Creatine Synthesis in Healthy Subjects Dietary Supplement: Creatine and Amino Acid supplement

Study Type: Interventional
Study Design: Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Basic Science
Official Title: Creatine Metabolism in Humans:Effect of Creatine and Amino Acid Supplement

Resource links provided by NLM:

Further study details as provided by Satish Kalhan, The Cleveland Clinic:

Primary Outcome Measures:
  • Quantification of creatine synthesis in healthy subjects [ Time Frame: 12/31/2012 ]

Secondary Outcome Measures:
  • Effect of creatine supplement on the rate of creatine synthesis [ Time Frame: 12/31/2012 ]

Enrollment: 15
Study Start Date: January 2010
Study Completion Date: December 2013
Primary Completion Date: June 2013 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Creatine and amino acid supplement Dietary Supplement: Creatine and Amino Acid supplement

Detailed Description:
Creatine and phosphocreatine are the major intracellular buffers for adenosine triphosphate. They also function as the energy shuttle for high energy phosphate from the mitochondrial site of production to the cytoplasmic site of utilization. In addition, creatine has been shown to affect satellite cell proliferation and differentiation and increase cell mitotic activity during compensatory hypertrophy in rat skeletal muscle. Creatine is synthesized from three amino acids: glycine, arginine and methionine. Although creatine metabolism has been studied extensively in the rat, the data regarding the kinetics of creatine and their regulation in humans are limited. This is in part due to a large and slow turning over pool of creatine and lack of good tracer methods. Using a recently developed stable isotopic tracer method (by us), we propose to quantify the rate of synthesis of creatine and its regulation in healthy subjects and in those with large skeletal muscle mass as a result of endurance training. In addition, the response to oral creatine administration on creatine kinetics will be quantified. The site of regulation will be identified by the relative rate of appearance of tracer glycine in guanidinoacetic acid and creatine. It is hypothesized that the fractional rate of synthesis of creatine will be higher in endurance trained subjects, and that creatine will suppress the rate of synthesis of creatine. Since creatine is critical for the maintenance of skeletal muscle mass and satellite cell proliferation, these data will provide the normative physiological data for future studies of subjects with manifest sarcopenia, such as aging, and those with chronic diseases, e.g. cirrhosis of liver. These data will form the basis for the studies of creatine metabolism in neurodegenerative disorders where creatine is being increasingly used as a therapeutic agent.

Ages Eligible for Study:   20 Years to 35 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Healthy controls and endurance trained subjects
  • Both males and females will be studied.

Exclusion Criteria:

  • any illness
  • on any medications and/or supplements
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT01725503

United States, Ohio
Cleveland Clinic
Cleveland, Ohio, United States, 44195
Sponsors and Collaborators
The Cleveland Clinic
Principal Investigator: Satish Kalhan, MD The Cleveland Clinic
  More Information

Responsible Party: Satish Kalhan, Principal Investigator, The Cleveland Clinic Identifier: NCT01725503     History of Changes
Other Study ID Numbers: 10-005
Study First Received: November 8, 2012
Last Updated: January 29, 2014

Keywords provided by Satish Kalhan, The Cleveland Clinic:
creatine synthesis processed this record on August 16, 2017