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

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01725503
Recruitment Status : Completed
First Posted : November 12, 2012
Last Update Posted : January 30, 2014
Information provided by (Responsible Party):
Satish Kalhan, The Cleveland Clinic

Brief Summary:

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 or disease Intervention/treatment Phase
Creatine Synthesis in Healthy Subjects Dietary Supplement: Creatine and Amino Acid supplement Not Applicable

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.

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 15 participants
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
Official Title: Creatine Metabolism in Humans:Effect of Creatine and Amino Acid Supplement
Study Start Date : January 2010
Actual Primary Completion Date : June 2013
Actual Study Completion Date : December 2013

Resource links provided by the National Library of Medicine

Arm Intervention/treatment
Experimental: Creatine and amino acid supplement Dietary Supplement: Creatine and Amino Acid supplement

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

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

Information from the National Library of Medicine

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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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): 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

Responsible Party: Satish Kalhan, Principal Investigator, The Cleveland Clinic Identifier: NCT01725503     History of Changes
Other Study ID Numbers: 10-005
First Posted: November 12, 2012    Key Record Dates
Last Update Posted: January 30, 2014
Last Verified: January 2014

Keywords provided by Satish Kalhan, The Cleveland Clinic:
creatine synthesis