[Note: Growth factors are proteins whose production is stimulated by growth hormone. They bind to receptors on the surface of cells, and act to activate cell growth/multiplication and inhibit programmed cell death. Insulin-like growth factor-1 also acts to help regulate blood glucose level.]
Journal: Journal of Rheumatology. 2007 Apr 1.
Authors and affiliations: Jones KD, Deodhar AA, Burckhardt CS, Perrin NA, Hanson GC, Bennett RM. Schools of Nursing and Medicine, Oregon Health and Science University, Portland, Oregon, USA.
Objective: People with Fibromyalgia often have low insulin-like growth factor-I (IGF-I) levels and a suboptimal growth hormone response to acute exercise. As previous work had demonstrated a normalization of the acute growth hormone response to exercise with the use of pyridostigmine (PYD), we tested the hypothesis that 6 months of PYD therapy plus supervised exercise would increase IGF-I levels.
Methods: Subjects with primary Fibromyalgia were randomized into 4 groups: (1) PYD/exercise; (2) PYD/diet recall; (3) placebo/exercise; and (4) placebo/diet recall.
The dosing of PYD was 60 mg tid for 6 months. Resting IGF-I levels were measured at baseline and after 6 months of treatment. In addition the acute growth hormone response to exercise at VO2 max was measured at baseline and after treatment.
Results: A total of 165 Fibromyalgia subjects (mean age 49.5 yrs, 5 male) were entered and 154 (93.3%) completed the study. Six months of therapy (PYD plus exercise or exercise alone) failed to improve the IGF-I levels.
The use of PYD 1 hour prior to exercise improved the acute growth response (4.54 ng/dl) compared to placebo (1.74 ng/dl) (p = 0.001) at the end of the 6-month trial. The acute growth hormone response to exercise at baseline did not correlate with IGF-I, age, depression, medications, estrogen status, or obesity.
Conclusion: A combination of triweekly supervised exercise plus the daily use of PYD for 6 months failed to increase IGF-I levels in patients with Fibromyalgia, despite the confirmation that PYD normalizes the acute growth hormone response to strenuous aerobic exercise.