GRGWPH HORMONE RESPONSE TO GROWTH HORMONE RELEASING FACTOR (GRF) IN SICKLE CELL DISEASE

Abstract

Many children with Sickle Cell Disease (SSD) have patterns of growth during childhood and adolescence consistent with constitutional delay in growth and pubertal development (CDGD). We evaluated the growth hormone (GH) response to a rapid intravenous infusion of growth hormone releasing factor (GRF 1-44, 1 ug/kg) in 6 children with Sickle Cell Disease whose growth patterns and bone ages were consistent with CDGD. The control population included children with (n=3) and, without (n=4) CDGD. Since the peak responses of the control children with and without CDGD were not different (32.3 +/-8.9, M +/- SD vs 26.5 +/- 2.5. M +/- SD, p>.05), these responses were combined for statistical analysis. All patients demonstrated normal GH responses to GRF stimulation. All patients had a peak GH response within 2 S.D. of the control mean peak GH response. The mean peak GH response of the patient population to GRF (29.2 +/- 14.3 ng/ml, M +/- SD), was not significantly different from the mean peak GH response of the combined control group (29.0 +/- 6.3. M +/- SD, P=.976). Further, when the peak GH responses of the patients with SSD (n=6) and the controls with delayed bone age (n=3) were combined, the mean peak GH response of the group with delayed bone ages was not different from that of the control children without retarded bone ages (30.2 +/- 12.2 M +/- SD, n=9 vs 26.5 +/- 2.5, M +/- SD, n=4, p=.567). SM-C levels were low for chronological age in 2 patients, in one of whom it was normal for bone age. These findings suggest that pituicyte GH response to GRF is intact and is not the cause of the observed impaired growth in patients with SSD.