Chronic growth hormone administration does not suppress endogenous growth hormone secretion in patients with neurosecretory growth hormone dysfunction.
Short children who respond normally to growth hormone (GH) stimulation, but have a subnormal spontaneous secretion of GH (neurosecretory GH dysfunction, NSD) are treated with exogenous GH which might suppress their endogenous GH secretion. The effect of chronic administration of GH (8-24 months) on plasma GH responses to GHRH, clonidine and spontaneous GH secretion were studied in 17 NSD patients. The diagnosis of NSD was based on a normal GH response to clonidine (greater than 10 micrograms/l) and an integrated concentration of (IC-GH) GH less than 3.2 micrograms/l. The GH dose used in this study was 0.25 IU/kg three times a week in 10 patients and 0.05 IU/kg daily in 7 patients. Insulin-like growth factor I levels (nmol) increased significantly on therapy from 9.3 +/- 3.8 to 24.4 +/- 22.4 (p less than 0.001). The GH response (microgram/l) to GHRH was 20.4 +/- 5.5 before treatment and 22.4 +/- 6.2 on GH. Peak GH after clonidine was 22.4 +/- 8.9 and 22.8 +/- 8.1, respectively. There was no significant decrease in the number of GH spontaneous peaks (1.8 +/- 0.7 vs. 2.0 +/- 0.7, respectively) or in the area under the curve. A subcutaneous GH bolus of 0.25 IU/kg in 4 patients resulted in a GH peak of 55-82 micrograms/l at 3-5 h and a gradual return to basal levels at 15-20 h after GH administration. The first spontaneous GH peak appeared 26-28 h after GH injection, peak amplitude was 10-15 micrograms/l.(ABSTRACT TRUNCATED AT 250 WORDS)
Zadik
Z
Z
Pediatric Endocrine Unit, Kaplan Hospital, Rehovot, Israel.
Limoni
Y
Y
Lieberman
E
E
D000365:Age Determination by Skeleton; D001827:Body Height / Q000187:drug effects; D015992:Body Mass Index; D002648:Child; D003000:Clonidine / Q000627:therapeutic use; D005260:Female; D007987:Gonadotropin-Releasing Hormone; D006130:Growth Disorders / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D013006:Growth Hormone / Q000097:blood / Q000378:metabolism* / Q000627:therapeutic use*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D008297:Male
D007987:Gonadotropin-Releasing Hormone; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D003000:Clonidine