GROWTH-HORMONE - INSULIN-LIKE GROWTH-FACTOR-I (IGF-I) AXIS IN PREPUBERTAL CHILDREN WITH CHRONIC-RENAL-FAILURE

The hypothalamic-pituitary insulin-like growth factor I(IGF-I) axis wa s evaluated in 12 children with chronic renal failure (CRF) aged 3.2 t o 16.5 yr (mean 9.5) on chronic dialysis, and in 13 renal transplantat ion patients aged 7.5 to 15.0 yr (mean 11.1). Height standard deviatio n score (SDS) was -2.8 +/- 0.5 ((X) over bar +/- SE) and -3.0 +/- 0.3 SDS (p=NS), and growth velocity was 3.7 +/- 0.4 and 1.5 +/- 0.3 cm/yea r (p<0.01), respectively. Mean nocturnal growth hormone (<(X)over bar GH>) and number of pulses >5 ng/ml in CRF and transplantation children were 4.2 +/- 0.8 vs 2.4 +/- 0.3 ng/ml, p=0.08 and 1.7 +/- 0.2 vs 1.0 +/- 0.2, p<0.05, respectively. In transplant children there was a posi tive correlation between <(X)over bar GH> and growth velocity (p<0.02) . GH peak response and the area under the curve post GH releasing horm one test were significantly higher in CRF and transplant children trea ted with deflazacort (new steroid derived from prednisolone) vs transp lant children treated with methylprednisone. Mean serum IGF-I levels w ere -0.5 +/- 0.2 SDS for chronological age (CA) in CRE patients and +0 .8 +/- 0.2 SDSCA in transplant patients, p=NS. In the latter, serum IG F-I values were positively correlated with growth velocity (p<0.02) an d negatively correlated with methyl-prednisone dose (p<0.05). Conclusi ons: Patients with CRF and growth retardation have a higher number of GH peaks and slightly elevated mean GH levels compared to transplant p atients. After renal transplantation GH secretion may be influenced by glucocorticoids as shown by the lower GH response to GHRH which impro ved with deflazacort and the inverse correlation between methylprednis one dose and IGF-I levels.