Pyridostigmine potentiates L-dopa- but not arginine- and galanin-induced growth hormone secretion in children.
The coadministration of growth hormone (GH) secretagogues can provide insight into the neuroregulation of GH secretion. The GH response to L-dopa (125, 250 and 500 mg orally for body weights less than 15 kg, between 15 and 30 kg and greater than 30 kg, respectively), arginine (Arg; 0.5 g/kg infused intravenously over 30 min) and galanin (GAL; 15 micrograms/kg infused intravenously over 60 min) when administered alone or combined with pyridostigmine (PD; 60 mg orally), a cholinergic agonist that likely acts via inhibition of endogenous somatostatin secretion, was studied in children with familial short stature. The GH-releasing effect of PD was also evaluated. In 8 children, PD and L-dopa when administered alone induced an equivalent GH rise (area under the response curve, mean +/- SEM: 241.4 +/- 31.1 vs. 202.9 +/- 38.6 micrograms/l/h) while their coadministration had an additive effect (435.4 +/- 41.4 micrograms/l/h; p less than 0.02 vs. PD and L-dopa alone). On the contrary, in other 8 children, PD and Arg induced similar GH increases either when administered alone (394.2 +/- 68.5 vs. 405.8 +/- 103.9 micrograms/l/h) or in combination (535.8 +/- 97.3 micrograms/l/h). GH increases almost superimposable were also observed when PD and GAL were administered alone (405.2 +/- 72.3 vs. 412.6 +/- 94.1 micrograms/l/h) or in combination (537.9 +/- 139.0 micrograms/l/h) in other 7 children. These data show that the enhancement of the cholinergic activity by PD increases the L-dopa-induced GH release but fails to modify both Arg- and GAL-induced GH release in short children.(ABSTRACT TRUNCATED AT 250 WORDS)
Ghigo
E
E
Department of Clinical Physiopathology, University of Turin, Italy.
Bellone
J
J
Imperiale
E
E
Arvat
E
E
Mazza
E
E
Valetto
M R
MR
Boffano
G M
GM
Cappa
M
M
Loche
S
S
De Sanctis
C
C
D000293:Adolescent; D001120:Arginine / Q000494:pharmacology*; D002648:Child; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D005260:Female; D019004:Galanin; D006130:Growth Disorders / Q000188:drug therapy; D013006:Growth Hormone / Q000378:metabolism*; D006801:Humans; D007980:Levodopa / Q000494:pharmacology*; D008297:Male; D009479:Neuropeptides / Q000009:adverse effects / Q000494:pharmacology*; D010455:Peptides / Q000009:adverse effects / Q000494:pharmacology*; D011729:Pyridostigmine Bromide / Q000009:adverse effects / Q000494:pharmacology*
D009479:Neuropeptides; D010455:Peptides; D007980:Levodopa; D019004:Galanin; D013006:Growth Hormone; D001120:Arginine; D011729:Pyridostigmine Bromide