Effect of growth hormone treatment on calcium kinetics in patients with osteogenesis imperfecta type III and IV.
Using a dual stable isotope technique, the effect of growth hormone (GH) on whole body calcium (Ca) metabolism was studied in children (ages 5-14 years) with type III (n = 9) and IV (n = 8) osteogenesis imperfecta. Each subject was studied twice: at baseline and following a GH (0.1-0.2 U/kg per day) treatment period of 1-1.5 years. Subjects were given 42Ca intravenously and 44Ca orally. The sera and urine 42Ca and 44Ca isotopic enrichments were followed over 7 days using thermal ionization mass spectrometry. The SAAM program was used to fit a three-compartment model to the tracer data. No significant differences were observed between: (1) children with type III and IV disease; or (2) baseline studies of boys and girls within each disease type. However, GH treatment significantly increased: (1) the exchangeable calcium pool (EP) in type III patients (2086 vs. 4422 mg/day, p = 0.02); and (2) the parameter associated with bone calcium accretion in type IV patients (Vo+: 973 vs. 1560 mg/day,p = 0.03) with boys responding with a significantly greater increase than girls (p = 0.008). Although not statistically significant, a trend toward an increase in Vo+ in type III patients and in EP in type IV was observed following treatment. Our observations imply that more Ca was available for bone mineralization following GH treatment in these subjects.
Vieira
N E
NE
Laboratory of Cellular and Molecular Biophysics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA. nevieira@box-n.nih.gov
Marini
J C
JC
Hopkins
E
E
Abrams
S A
SA
Yergey
A L
AL
D000293:Adolescent; D002113:Calcification, Physiologic / Q000187:drug effects; D002118:Calcium / Q000097:blood* / Q000652:urine*; D002648:Child; D002675:Child, Preschool; D005260:Female; D013006:Growth Hormone / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D008297:Male; D010013:Osteogenesis Imperfecta / Q000188:drug therapy* / Q000378:metabolism* / Q000503:physiopathology
D013006:Growth Hormone; D002118:Calcium