Normal growth hormone (GH) response to GH-releasing hormone in children with thalassemia major before puberty: a possible age-related effect.
The plasma GH response to a single iv bolus dose of 2 micrograms/kg BW synthetic GHRH-(1-44)NH2 was evaluated in 13 prepubertal children with thalassemia major (mean age, 7.6 +/- 0.8 yr) with growth retardation and in 15 prepubertal children with nonendocrine short stature. All of the patients showed a significant increase in plasma GH concentration, with a mean peak of 31.4 +/- 4.5 micrograms/L at 15 min (P less than 0.001 vs. basal values; range, 18.4-65 micrograms/L) after GHRH, which was not different from that of the control group of idiopathic short stature children (40.1 +/- 3.4 micrograms/L; range, 21-65.4 micrograms/L). All but 1 of the thalassemic patients had a normal GH response to the arginine-insulin stimulation test. The mean plasma insulin-like growth factor-I level was low (0.12 +/- 0.05 U x 10(3)/L; range, less than 0.02-0.61 U x 10(3)/L). Analysis of these results as well as previously reported data indicating that older thalassemic patients have an impaired GH response indicates that there may be an age-related pituitary and/or hypothalamic dysfunction in thalassemic children. This study also confirms that the insulin-like growth factor-I decrease occurs before any alteration in GH secretion. These changes might play a role in the early growth retardation that occurs in these patients.
Leger
J
J
Pediatric Endocrinology Unit, Hôpital des Enfants Malades, Paris, France.
Girot
R
R
Crosnier
H
H
Postel-Vinay
M C
MC
Rappaport
R
R
D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D004392:Dwarfism / Q000097:blood / Q000150:complications; D005260:Female; D013006:Growth Hormone / Q000097:blood*; D013007:Growth Hormone-Releasing Hormone / Q000494:pharmacology*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000097:blood; D008297:Male; D011627:Puberty; D013789:Thalassemia / Q000097:blood* / Q000150:complications; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood
D007334:Insulin-Like Growth Factor I; D013972:Thyrotropin; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone; D013974:Thyroxine