24-HOUR PLASMA GROWTH-HORMONE (GH) PROFILES, URINARY GH EXCRETION, AND PLASMA INSULIN-LIKE GROWTH FACTOR-I AND FACTOR-II LEVELS IN PREPUBERTAL CHILDREN WITH CHRONIC RENAL-INSUFFICIENCY AND SEVERE GROWTH-RETARDATION

We studied 24-h plasma GH profiles, maximal GH responses to arginine provocation and insulin-like growth factor-I (IGF-I) and IGF-II levels in plasma in 22 euthyroid prepubertal children (mean age, 9.5 yr) with chronic renal insufficiency (glomerular filtration rate, <20 mL/min-1.73 m2) and severe growth retardation [mean (±SD) height SD score (SDS), -2.8 (1.1)]. The 24-h GH profiles were analyzed using the Pulsar program. Girls had significantly higher 24-h GH secretion than boys (P < 0.004). Children with end-stage nephrotic syndrome had higher baseline GH levels and total area under the curve (AUCo) than patients with dysplastic kidneys (P < 0.05), while the area under the curve above baseline (AUCb) was similar in all types of renal diseases. The type of treatment (conservative, peritoneal, hemodialysis) did not significantly influence the 24-h GH secretion. No correlation was found between 24-h GH profiles and age, height SDS for chronological age, height velocity SDS for bone age, and weight for height. Fourteen children showed a normal 24-h GH profile, defined as a GH profile with well defined, regular GH peaks returning to baseline GH levels and a distinct day and night pattern (AUCb, 90–300 μg/L.24 h). Four children had low profiles, with GH peaks below 10 μg/L, returning to baseline GH levels and occurring almost exclusively during the night (AUCb, <90 μg/ L.24 h). The remaining four children had elevated 24-h GH profiles, with GH peaks on top of elevated baseline GH levels of more than 3 μg/L (AUCb, 35–205 μg/L.24 h; AUCo >300 μg/L 24 h). In all patients 24-h urinary GH and β2-globulin excretion was 100–1000 times higher than that in controls. The urinary GH excretion correlated significantly with all characteristics of the 24-h GH profiles (r = 0.57–0.59; P < 0.05). The maximal GH response during the arginine tolerance test was normal in 66% of the children. The mean (±SD) SDS for bone age for the IGF-I plasma levels was +1.1 (1.9), and that for IGF-II was +3.6 (3.4). IGF-I levels correlated significantly with the AUCb, maximum GH, and GH peak characteristics of the 24-h GH profiles (r = 0.05–0.73; P < 0.02–0.001). IGF-II levels did not show any correlation with the characteristics of the endogenous GH secretion. We conclude that many children with end-stage chronic renal insufficiency and severe growth retardation have normal endogenous GH secretion and normal to high levels of IGF-I and -II despite increased urinary GH excretion. © 1990 by The Endocrine Society.