A Controlled Study on Serum Insulin-Like Growth Factor 1 (Somatomedin C) Levels in Fibromyalgia

섬유근통 증후군 환자에서 Somatomedin C (Insulin-Like Growth Factor 1)의 농도와 임상증상과의 관계

Background: Fibromyalgia is a common syndrome of musculoskeletal pain and fatigue. Lacking distinctive histological or laboratory abnormality in diagnosis, it has often been considered a form of "psychogenic rheumatism". Fibromyalgia causes much distress to the affected patients and often frustrates physicians, who are unable to start rational therapy on any logical disease pathology. Methods: Growth hormone is essential for muscular homeostasis. In the present study, the notion that the stage-4 sleep anomaly typically seen in the fibromyalgia syndrome may disrupt growth hormone secretion was tested. Because growth hormone has a very short half-life, serum levels of somatomedin C were measured; somatomedin C is the major mediator of growth hormone's anabolic actions and is a prerequisite for normal muscle homeostasis. Serum levels of somatomedin C using acid-extraction procedure and two-site immunoradiome-tric assay (IRMA) and number of tender points were measured in 27 female patients with fibromyalgia from 40 to 60 years old and 27 healthy controls. Results: There were no differences in the concentration of somatomedin C between fibromyalgia patients and controls ($mean{\pm}SD$: $178.3{\pm}75.5$ ng/ml versus $166.3{\pm}76.6$ ng/ml; p=0.55). And there were no correlations between number of tender point and serum somatomedin C level by linear regression analysis. Conclusions: These findings did not support that there is a distinctive disruption of the growth hormone-somatomedin C neuroendocrine axis in a fibromyalgia syndrome. But we can not discard the hypothesis that disturbed sleep predispose to muscle pain.