SOMATOMEDIN-C (INSULIN-LIKE-GROWTH-FACTOR-I) LEVELS IN PATIENTS WITH CHRONIC-FATIGUE-SYNDROME

Chronic fatigue syndrome is a disorder clinically quite similar to fib romyalgia syndrome, and it is of interest to examine if these two synd romes have pathogenetic as well as clinical features in common. Somato medin C levels have been found to be lower in patients with fibromyalg ia syndrome than in healthy controls. An attractive hypothesis relatin g sleep disturbance, altered somatotropic neuroendocrine function and fibromyalgia symptoms has been put forward as a plausible pathogenic m echanism for fibromyalgia syndrome. We therefore sought to investigate the level of somatomedin C in patients with chronic fatigue syndrome. Somatomedin C levels were determined by radioimmunoassay in frozen se rum specimens from 49 patients with CFS and 30 healthy blood donor con trol subjects of similar age and gender. Somatomedin C levels were hig her in patients with CFS than in healthy control subjects (255.3 +/- 6 8.5 vs 211.9 +/- 76.2, P = 0.01). There was no effect of gender, use o f nonsteroidal anti-inflammatory drugs or tricyclic drugs on levels of somatomedin C. There was a tendency for somatomedin C levels to fall with age. In contrast to patients with fibromyalgia, in whom levels of somatomedin C have been found to be reduced, levels in patients with CFS were found to be elevated. Thus, despite the clinical similarities between these two conditions, they may be associated with different a bnormalities of sleep and/or of the somatotropic neuroendocrine axis. (C) 1997 Elsevier Science Ltd.