Growth hormone secretion in poorly growing children with renal hypophosphataemic rickets.
We evaluated growth hormone (GH) secretion and baseline serum free insulin-like growth factor-I (IGF-I) levels in 12 poorly growing patients (5 males and 7 females; age 1.6-12.5 years, median 6.4) with renal hypophosphataemic rickets treated with 1,25-dihydroxy-vitamin D3 plus inorganic oral phosphate salts. Eleven healthy normally growing children (6 males and 5 females; age 3.1-10.8 years, median 6.6) were studied as control group. All patients had a normal GH response (GH peak > or = 10 micrograms/l) to at least one provocative pharmacological stimulus (levodopa or insulin tolerance test), as well as all the controls. Mean growth hormone concentrations (MGHC), mean pulse amplitude, number of GH peaks above 5 micrograms/l, and IGF-I values overlapped between patients and controls, even though four patients had MGHC below the lower limit of MGHC of controls. In these patients, however, height-SDS, serum calcium, phosphate, alkaline phosphatase, intact parathyroid hormone, 1,25-dihydroxyvitamin D concentrations and maximum tubular phosphate reabsorption/glomerular filtration rate ratio did not differ in respect to the patients who showed MGHC in the range of controls (n = 6). MGHC IGF-I and biochemical parameters of phospho-calcium metabolism did not differ when the patients were subdivided in two groups on the basis of the median (-2.4) of height-SDS. No relationship was found between MGHC or IGF-I and height-SDS or growth velocity-SDS. Height-SDS and years of treatment or age at which therapy was started were not related.(ABSTRACT TRUNCATED AT 250 WORDS)
Saggese
G
G
Department of Pediatrics, University of Pisa, Italy.
Baroncelli
G I
GI
Bertelloni
S
S
Perri
G
G
D002648:Child; D002675:Child, Preschool; D005260:Female; D006130:Growth Disorders / Q000378:metabolism*; D013006:Growth Hormone / Q000378:metabolism*; D006801:Humans; D007015:Hypophosphatemia, Familial / Q000378:metabolism*; D007223:Infant; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism*; D008297:Male; D012044:Regression Analysis; D012279:Rickets / Q000378:metabolism*
D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone