Somatomedin and growth after renal transplantation

Hormonal and metabolic factors which influence growth were studied in nine growth-retarded uremic children who received renal homografts. Post-transplant growth velocity based on bone age (GVBA) became normal in four (88–103%), accelerated in two (127–139%), and remained subnormal in three (18–50%). Serum somatomedin (SM), was very low in all children before transplant (0.39 ± 0.10 U/ml), but rose in each child after transplantation. Post-transplant somatomedin (0.84 ± 0.14 U/ml) was not significantly different from the somatomedin of eight healthy male control subjects matched for bone age (1.03 ± 0.16). Post-transplant GVBA was directly correlated (P < 0.05) with serum somatomedin and creatinine clearance (C_cr), but was not related to stimulated growth hormone response or to other variables of endocrine function. The data suggested that the growth failure in our patients with severe chronic uremia was due, at least in part, to lack of serum somatomedin. However, in four of five patients with persisting moderate azotemia (C_er 11.8–42.5 ml/min/1.73 m²), subnormal growth continued despite relatively normalized serum somatomedin activity. Three of the four poorly growing azotemic patients had the highest average steroid dosages in the group (prednisolone > 9.1 mg/m²/24 hr). If low serum somatomedin activity develops in the course of end stage renal disease in children, growth retardation may be the consequence. After renal transplantation normalization of serum somatomedin activity may be a necessary although not sufficient condition for the resumption of growth.