A DGReview of:”Impaired growth hormone secretion in fibromyalgia patients: Evidence for augmented hypothalamic somatostatin tone”
Source: Arthritis & Rheumatism Volume 46, Issue 5, 2002
By Anne MacLennan
Women with fibromyalgia have an impaired growth hormone response to exercise that is reversible with pyridostigmine.
This impaired response exists even in fibromyalgia (FM) patients with normal levels of insulin-like growth factor-one (IGF-one), Eduardo S. Paiva and colleagues from Oregon Health Sciences University, Portland, Oregon, United States, have found.
Because pyridostigmine reduces somatostatin tone, this defective growth hormone (GH) response may result from higher levels of somatostatin, a hypothalamic hormone that inhibits GH secretion, these authors surmise.
The two-fold objective of this study was to determine the GH response to acute exercise stressor in female FM patients and to assess the importance of somatostatin tone in the generation of this response.
Twenty women with FM and 10 healthy female controls, all of whom exercised on a treadmill to their own idea of exhaustion, were monitored for pulse, blood pressure, electrocardiography, oxygen uptake, carbon dioxide output, anaerobic threshold and maximal workload. Researchers drew blood for GH and cortisol measures one hour before exercise, and then again immediately before, immediately after and one hour after exercise.
This entire procedure was precisely repeated one month later, except now all of the women received pyridostigmine bromide (Mestinon; 30 mg orally) one hour before exercise.
Although FM patients versus controls showed no GH or cortisol response to exercise, their GH levels increased eight-fold after receiving the pyridostigmine to a value comparable with that of controls.
In the FM patients, pyridostigmine did not increase the cortisol response to exercise and did not alone stimulate GH secretion, nor did it improve exercise-induced GH secretion in controls.
FM patients with normal IGF-one levels were also found to have an impaired GH response to exercise.
Arthritis & Rheumatism Volume 46, Issue 5, 2002. Pages: 1344-1350.
Impaired growth hormone secretion in fibromyalgia patients: Evidence for augmented hypothalamic somatostatin tone
Eduardo S. Paiva, Atul Deodhar, Kim D. Jones, Robert Bennett *
Oregon Health Sciences University, Portland
*Correspondence to Robert Bennett, Department of Medicine (OP09), Oregon Health Sciences University, Portland, OR 97201
USPHS; Grant Number: 5-M01-RR-00334
Objective: To determine whether female fibromyalgia (FM) patients exhibit a normal growth hormone (GH) response to an acute exercise stressor, and to assess the importance of somatostatin tone in the generation of this GH response.
Methods: Twenty female FM patients were compared with 10 healthy female controls. All subjects exercised to volitional exhaustion on a treadmill. A standard metabolic cart was used to monitor pulse, blood pressure, electrocardiography, oxygen uptake, carbon dioxide output, anaerobic threshold, and maximal workload. Blood was drawn for GH and cortisol measurements 1 hour before exercise, immediately before exercise, immediately after exercise, and 1 hour after exercise. One month later, testing that was exactly similar was performed, except all subjects were given pyridostigmine bromide (Mestinon; 30 mg orally) 1 hour before exercise.
Results: Compared with controls, FM patients failed to exhibit a GH or cortisol response to acute exercise (P = 0.003). After administration of pyridostigmine, 1 hour before exercise, the GH levels of FM patients increased 8-fold (P = 0.001), to a value comparable with that of controls.
Pyridostigmine did not increase the cortisol response to exercise in FM patients. Pyridostigmine alone did not stimulate GH secretion in FM patients, nor did it improve exercise-induced GH secretion in controls. FM patients with normal insulin-like growth factor 1 (IGF-1) levels had an impaired GH response to exercise.
Conclusion: Three new findings are reported: 1) FM patients have a reduced GH response to exercise, 2) pyridostigmine reverses this impaired response, and 3) defective GH secretion in FM can occur in patients with normal IGF-1 levels. Because pyridostigmine is known to reduce somatostatin tone, it is surmised that the defective GH response to exercise in FM patients probably results from increased levels of somatostatin, a hypothalamic hormone that inhibits GH secretion.
Received: 5 June 2001; Accepted: 5 December 2001