Serum somatomedin A and non-dialyzable urinary hydroxyproline in girls with idiopathic scoliosis.

Serum somatomedin A was determined by radioreceptor assay in 31 girls with idiopathic scoliosis and 30 controls, with ages ranging from 9.7-16.2 years. In the material as a whole no significant difference could be found between scoliotics and controls. Similarly no differences were found in the girls under 13 years of age. However, in girls older than 13 years the controls had significantly higher somatomedin A levels than the scoliotics. In the second part of the study 26 girls with idiopathic scoliosis and 22 controls were examined with regard to the urinary excretion of non-dialyzable hydroxyproline,. which has been suggested to be correlated with collagen synthesis. The percentage non-dialyzable fraction of the total hydroxyproline was found to be significantly higher in the control girls. The mean age was 12.8 years for both groups. The results suggest a higher growth rate in the controls than in the scoliotics for girls over 12 years. There is, however, no definite evidence as to the function of the somatomedins or of the relationship between non-dialyzable hydroxyproline and growth.