Stimulation of growth hormone secretion in children with X-linked hypophosphatemia.
X-linked hypophosphatemia is characterized by low serum phosphorus, relative vitamin D deficiency and rickets. Despite adequate metabolic control with oral phosphate and vitamin D therapy, patients with X-linked hypophosphatemia have short stature. Whether growth hormone (GH) deficiency plays a role in short stature in patients with X-linked hypophosphatemia is not known. The purpose of this report was to investigate the response of GH to sequential paired pharmacological stimulation in patients with X-linked hypophosphatemia. Basal GH was 3.8 +/- 0.7 ng/ml, insulin-like growth factor-I (IGF-I) was 225 +/- 38 ng/ml and IGF binding protein-3 was 3.0 +/- 0.2 mg/l in 16 children studied with X-linked hypophosphatemia. In response to L-dopa and arginine hydrochloride stimulation, serum GH rose to above 7 mg/ml in all patients. Thus, the short stature in patients with X-linked hypophosphatemia is not due to a GH/IGF-I secretory defect.
Seikaly
M G
MG
University of Texas Southwestern Medical Center, Dallas 75235-9063, USA.
Baum
M
M
D000293:Adolescent; D001120:Arginine / Q000494:pharmacology*; D001827:Body Height; D002648:Child; D002675:Child, Preschool; D005260:Female; D006130:Growth Disorders / Q000097:blood / Q000209:etiology*; D013006:Growth Hormone / Q000097:blood / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D007015:Hypophosphatemia, Familial / Q000097:blood* / Q000150:complications; D007223:Infant; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D007980:Levodopa / Q000494:pharmacology*; D008297:Male; D013268:Stimulation, Chemical
D007980:Levodopa; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D001120:Arginine