The Effect of Vitamin C on Growth Hormone Secretion
试验速览
- 阶段
- 2 期
- 状态
- 撤回
- 试验地点
- 2
- 主要终点
- Change from Baseline in GH secretion at 4 weeks
研究概览
简要总结
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.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
入排标准
- 年龄范围
- 18 Years 至 60 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Men and women age 18-60
- •BMI ≥ 30 kg/m2
- •Waist circumference ≥ 102 cm in men and ≥ 88 cm in women
- •Plasma vitamin C concentration ≤ 23 µmol/l
- •Peak stimulated GH ≤ 4.2 µg/l upon GHRH-arginine stimulation test
排除标准
- •History of hypopituitarism, pituitary surgery, pituitary/brain radiation, recent traumatic brain injury or any other condition known to affect the GH axis.
- •History of severe chronic illness including anemia, chronic kidney disease, liver disease, oxygen dependent COPD or HIV
- •Subjects on testosterone, glucocorticoids, anabolic steroids, GHRH, GH or IGF-1 within 3 months of enrollment
- •Use of dietary supplements including vitamin C or once daily multi-vitamins
- •Subjects with Hgb < 912 g/dL, SGOT > 2.5x upper limit of normal or Creatinine > 1.5 mg/dL
- •Subjects with poorly controlled diabetes, defined as HbA1c > 8%.
- •Changes in lipid lowering or anti-hypertensive regimen within 3months of screening
- •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
- •Any condition judged by the patient's physician to cause this clinical trial to be detrimental to the patient.
结局指标
主要结局
Change from Baseline in GH secretion at 4 weeks
时间窗: 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.
次要结局
未报告次要终点
研究者
Hideo Makimura
Assistant Professor of Medicine
Massachusetts General Hospital