Somatostatin infusion withdrawal: studies in normal children and in children with growth hormone deficiency.
Withdrawal of a somatostatin infusion (SSIW) is followed by a rebound rise of GH in both animals and normal adult men, a phenomenon likely mediated by endogenous GHRH function. In the present study, we have evaluated the GH response to SSIW in a group of 28 prepubertal children (18 boys and 10 girls; aged 3.7-11.1 yr). Six children had GH deficiency [GHD; GH responses to pyridostigmine (PD)+GHRH and to clonidine <20 and <7 microg/L, respectively], 4 children had GH neurosecretory dysfunction (GHND; GH responses to PD+GHRH and to clonidine > or =20 and >7 microg/L, respectively; mean integrated nighttime GH concentrations <3 microg/L), and 18 children were short normal children [normal controls (NC)]. All children received a constant infusion of SS at the dose of 3 microg/Kg x h for 90 min. SSIW elicited a clear-cut GH rise in NC children (13.7+/-1.0 microg/L), but not in GH-deficient children, regardless of the underlying etiology (GHD, 1.6+/-0.4 microg/L; GHND, 2.4+/-0.3 microg/L). The GH response to SSIW was similar between GHD and GHND children. There was no overlapping of the maximum SSIW-stimulated GH peaks between NC and GHD or GHND children. In conclusion, we have demonstrated that SSIW elicits a significant GH rise in NC children, but not in GH-deficient children, regardless of the underlying etiology (GHD or GHND). This resulted in complete discrimination of NC from GHD or GHND children. Were these present findings confirmed on a larger number of children, SSIW, because of its testing efficaciousness and safety, procedural simplicity, and economy holds promise of being a useful diagnostic tool for GH-dependent growth disorders.
Cappa
M
M
Divisione di Pediatria, Ospedale Bambino Gesù, Roma, Italy.
Rigamonti
A E
AE
Bizzarri
C
C
Porzio
O
O
Civolani
P
P
Cella
S G
SG
Loche
S
S
Müller
E E
EE
D000316:Adrenergic alpha-Agonists; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003000:Clonidine; D005260:Female; D019382:Human Growth Hormone / Q000097:blood* / Q000172:deficiency* / Q000378:metabolism; D006801:Humans; D008297:Male; D011729:Pyridostigmine Bromide; D013004:Somatostatin / Q000008:administration & dosage*
D000316:Adrenergic alpha-Agonists; D019382:Human Growth Hormone; D013004:Somatostatin; D011729:Pyridostigmine Bromide; D003000:Clonidine