Growth Hormone, Cardiovascular Risk, and Visceral Adiposity

Growth Hormone, Cardiovascular Risk, and Visceral Adiposity

This study will compare growth hormone levels and cardiovascular risk markers in normal weight and overweight women and men. In women and men with increased abdominal weight, growth hormone (GH) versus placebo will be administered and effects on cardiovascular risk, insulin resistance and body composition will be measured.

The purpose of this study is to measure growth hormone levels in women and men who are normal weight, overweight, and obese. Growth hormone levels will be correlated with body weight, body composition, and markers of cardiovascular risk. In overweight or obese women and men with increased visceral adiposity and below average IGF-1 levels, growth hormone versus placebo will be given for 6 months. Effects of growth hormone treatment on weight, body composition, insulin resistance, lipids, and cardiovascular risk markers will then be assessed. Study subjects will be followed for an additional six months for these endpoints.

Inclusion Criteria:

• For growth hormone measurement part (for men and women):

  1. For visceral adiposity arm: waist circumference greater than or equal to 88 cm for women or 102 cm for men, and BMI greater than or equal to 25 kg/m2
  2. For lean controls: BMI 18.5 to 24.9 kg/m2

• For growth hormone treatment part (for men and women):

  1. Visceral adiposity (waist circumference greater than or equal to 88 cm for women and 102 for men, BMI greater than or equal to 25 kg/m2)
  2. IGF-I within the lowest 2 quartiles for age and gender
  3. Willingness to maintain current activity level and diet

Exclusion Criteria:

• Diabetes mellitus (fasting plasma glucose greater than 126 mg/dL or 2-hour post-oral glucose tolerance test [OGTT] plasma glucose greater than 200)
• Taking the following medications in the last 3 months: weight loss or lipid-lowering agents, medications to treat diabetes mellitus or "pre-diabetes", oral contraceptives or estrogen-containing medications, other medications known to significantly affect weight
• Smoking
• Hematocrit below the lower limit of normal
• Amenorrhea for 3 months (in women)
• Pregnant or breastfeeding (in women)
• Polycystic ovary syndrome (in women)
• Weight that exceeds 280 pounds
• SGPT greater than 2 times the upper limit of normal
• History of malignancy, except for fully resolved basal cell carcinomas of the skin (Specific Aim 2 only)
• Radiation exposure greater than 1000 mrem over the last 12 months
• Previous diagnosis of cardiovascular disease
• History of pituitary or hypothalamic disease, brain radiation, or childhood growth hormone deficiency
• History of carpal tunnel syndrome that has not been surgically treated