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The Effect of Vitamin C on Growth Hormone Secretion

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ClinicalTrials.gov Identifier: NCT01537094
Recruitment Status : Withdrawn (Unable to obtain funding to initiate the study. No subjects were enrolled.)
First Posted : February 23, 2012
Last Update Posted : December 13, 2013
Information provided by (Responsible Party):
Hideo Makimura, Massachusetts General Hospital

Brief Summary:
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 or disease Intervention/treatment 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

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 0 participants
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
Study Start Date : December 2013
Actual Primary Completion Date : December 2013
Actual Study Completion Date : December 2013

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Hormones Vitamin C

Arm Intervention/treatment
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

Primary Outcome Measures :
  1. 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.

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

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.

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

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United States, Massachusetts
Massachusetts General Hospital
Boston, Massachusetts, United States, 02114
Sponsors and Collaborators
Massachusetts General Hospital
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Principal Investigator: Hideo Makimura, MD, PhD Massachusetts General Hospital
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Responsible Party: Hideo Makimura, Assistant Professor of Medicine, Massachusetts General Hospital
ClinicalTrials.gov Identifier: NCT01537094    
Other Study ID Numbers: 2011-P-002912
First Posted: February 23, 2012    Key Record Dates
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:
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Congenital Abnormalities
Ascorbic Acid
Physiological Effects of Drugs
Molecular Mechanisms of Pharmacological Action
Protective Agents