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The Effect of Vitamin C on Growth Hormone Secretion

This study has been withdrawn prior to enrollment.
(Unable to obtain funding to initiate the study. No subjects were enrolled.)
Sponsor:
ClinicalTrials.gov Identifier:
NCT01537094
First Posted: February 23, 2012
Last Update Posted: December 13, 2013
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.
Information provided by (Responsible Party):
Hideo Makimura, Massachusetts General Hospital
  Purpose
Obesity is associated with reduced growth hormone (GH) secretion. GH secretion is regulated by nutritional stimuli including fasting, insulin, glucose and free fatty acids. However, the role of micronutrients, such as vitamins, on GH secretion has not been investigated in much detail. Vitamin C levels are also reduced in obesity, and the investigators recently demonstrated a possible role for dietary vitamin C intake in the regulation of GH secretion in two preliminary retrospective studies. The investigators therefore propose a more detailed prospective physiological study to examine the effects of increasing dietary vitamin C intake on GH secretion in a physiologic, intervention study. The investigators hypothesize that increasing vitamin C concentrations in obese subjects with sub-optimal plasma vitamin C levels and reduced GH secretion will increase GH secretion.

Condition Intervention Phase
Obese Disorder of Vitamin C Growth Hormone Secretion Abnormality Dietary Supplement: Placebo Dietary Supplement: Vitamin C 250 mg once daily Dietary Supplement: Vitamin C 1,000 mg once daily Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: The Effect of Vitamin C on Growth Hormone Secretion

Resource links provided by NLM:


Further study details as provided by Hideo Makimura, Massachusetts General Hospital:

Primary Outcome Measures:
  • Change from Baseline in GH secretion at 4 weeks [ Time Frame: Change from Baseline to 4 weeks ]
    GH secretion will be assessed by overnight frequent blood sampling to assess maximum GH, nadir GH, mean overnight GH, as well as parameters of pulsatile secretion.


Enrollment: 0
Study Start Date: December 2013
Study Completion Date: December 2013
Primary Completion Date: December 2013 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: Vitamin C low dose
vitamin C 250 mg oral once daily
Dietary Supplement: Vitamin C 250 mg once daily
Active Comparator: Vitamin C high dose
vitamin C 1,000 mg oral once daily
Dietary Supplement: Vitamin C 1,000 mg once daily
Placebo Comparator: Placebo
Placebo oral once daily
Dietary Supplement: Placebo

  Eligibility

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 60 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  1. Men and women age 18-60
  2. BMI ≥ 30 kg/m2
  3. Waist circumference ≥ 102 cm in men and ≥ 88 cm in women
  4. Plasma vitamin C concentration ≤ 23 µmol/l
  5. Peak stimulated GH ≤ 4.2 µg/l upon GHRH-arginine stimulation test

Exclusion Criteria:

  1. History of hypopituitarism, pituitary surgery, pituitary/brain radiation, recent traumatic brain injury or any other condition known to affect the GH axis.
  2. History of severe chronic illness including anemia, chronic kidney disease, liver disease, oxygen dependent COPD or HIV
  3. Subjects on testosterone, glucocorticoids, anabolic steroids, GHRH, GH or IGF-1 within 3 months of enrollment
  4. Use of dietary supplements including vitamin C or once daily multi-vitamins
  5. Subjects with Hgb < 912 g/dL, SGOT > 2.5x upper limit of normal or Creatinine > 1.5 mg/dL
  6. Subjects with poorly controlled diabetes, defined as HbA1c > 8%.
  7. Changes in lipid lowering or anti-hypertensive regimen within 3months of screening
  8. Subject is currently enrolled in another investigational device or drug trial(s), or subject has received other investigational agent(s) within 28 days of baseline visit
  9. Any condition judged by the patient's physician to cause this clinical trial to be detrimental to the patient.
  Contacts and Locations
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 ClinicalTrials.gov identifier (NCT number): NCT01537094


Locations
United States, Massachusetts
Massachusetts General Hospital
Boston, Massachusetts, United States, 02114
Sponsors and Collaborators
Massachusetts General Hospital
Investigators
Principal Investigator: Hideo Makimura, MD, PhD Massachusetts General Hospital
  More Information

Responsible Party: Hideo Makimura, Assistant Professor of Medicine, Massachusetts General Hospital
ClinicalTrials.gov Identifier: NCT01537094     History of Changes
Other Study ID Numbers: 2011-P-002912
First Submitted: February 10, 2012
First Posted: February 23, 2012
Last Update Posted: December 13, 2013
Last Verified: December 2013

Keywords provided by Hideo Makimura, Massachusetts General Hospital:
low vitamin c
reduced growth hormone secretion

Additional relevant MeSH terms:
Vitamins
Ascorbic Acid
Hormones
Micronutrients
Growth Substances
Physiological Effects of Drugs
Hormones, Hormone Substitutes, and Hormone Antagonists
Antioxidants
Molecular Mechanisms of Pharmacological Action
Protective Agents