Growth Hormone Treatment on Phosphocreatine Recovery in Obesity

Massachusetts General Hospital15 enrolled

Overview

Obesity is associated with reduced growth hormone (GH) secretion. Reduced GH secretion in obesity is associated with increased cardiovascular disease risk. However, it is not yet known how reduced GH increases cardiovascular disease risk in obesity. The investigators hypothesize that reduced GH contributes to dysfunction of the mitochondria. Therefore, the investigators hypothesize that treatment of obese subjects with reduced GH secretion with GH will improve mitochondrial function and that this improvement in mitochondrial function will contribute, in part, to the effects of GH to improve metabolic parameters in obesity. The investigators propose to study skeletal muscle mitochondria in obese subjects with reduced GH secretion using magnetic resonance spectroscopy and muscle biopsies before and after treatment with GH.

Study Type

INTERVENTIONAL

Allocation

NON_RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Enrollment

Conditions

Obese Growth Hormone Secretion Abnormality

Interventions

Eligibility

Sex: MALEMin age: 18 YearsMax age: 60 Years

Medical Language ↔ Plain English

Inclusion Criteria: 1. Men age 18-60 years old 2. BMI ≥ 30 kg/m2 3. Waist circumference ≥ 102 cm 4. Peak GH value of ≤ 4.2 μg/l on standard GHRH-arginine stimulation test Exclusion Criteria: 1. Obesity due to a known secondary cause (Cushing's syndrome, hypothyroidism, etc) or a history of gastric bypass procedure. 2. Subjects who have a known history of diabetes, fasting blood sugar \>125 mg/dl or using any anti-diabetic drugs. 3. Use of Aspirin, Clopidogrel (Plavix), Warfarin (Coumadin) or other anti-coagulants 4. Subjects on testosterone, glucocorticoids, anabolic steroids, GHRH, GH or IGF-1 within 3 months of enrollment. 5. Changes in lipid lowering or anti-hypertensive regimen within 3 months of screening 6. History of pituitary tumor, hypopituitarism, pituitary surgery, pituitary/brain radiation or traumatic brain injury or any other condition known to affect the GH axis. 7. Severe chronic illness including HIV, active malignancy or history of colon cancer. 8. Hemoglobin \< 9.0 g/dL, SGOT \> 2.5 x upper limit normal, Creatinine \>1.5 mg/dL, or PSA \>5 ng/ml. 9. 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. 10. Any condition judged by the patient's physician to cause this clinical trial to be detrimental to the patient. 11. Contraindications to MRI scanning.

Outcomes

Primary Outcomes

Phosphocreatine Recovery

The primary objective of this study is to determine the effects of growth hormone on mitochondrial function as assessed by 31P-MRS in obese subjects with reduced GH secretion. Mitochondrial function was represented by ViPCr, a measure of phosphocreatine recovery after sub-maximal exercise. Univariate regression analyses was performed to assess the relationship between the change in skeletal muscle IGF-1 mRNA after 12 weeks treatment with rhGH to change in ViPCr.

Time frame: 12-weeks