Low serum somatomedin activity in celiac disease. A misleading aspect in growth failure from asymptomatic celiac disease.

In 4 children with celiac disease, aged 7 months to 11 years, serum somatomedin activities (SMA) were consistently low: less than 0.40 U/ml (N greater than 0.50 U/ml). Basal plasma growth hormone (GH) levels were not elevated and increased normally under arginine-insulin stimulation in 3 patients. Human GH administration at a dosage which usually determines an increase of serum SMA in children with GH deficiency (4 mg/day/2 days) did not modify significantly the low serum SMA. However, in 1 child a clear-cut increase of serum SMA (0.22-0.82 U/ml) was noted under a higher dosage of human GH (8 mg/day/2 days). In 3 patients serum SMA was studied 3 weeks to 4 months after starting the gluten-free diet and was found to be normal. A limitation of the somatomedin generation unrelated to a deficit in GH secretion and probably resistant to GH appears therefore to be present in celiac disease. The rapid normalization of serum SMA under gluten-free diet suggests that the low serum SMA is induced through some unknown hormonal or metabolic signal by the protein malabsorption and/or the nutritional deficiency present in celiac disease.