Circulating levels of incretin hormones and amylin in the fasting state and after oral glucose in GH-deficient patients before and after GH replacement: a placebo-controlled study.
Eur J Endocrinol
; 143(5): 593-9, 2000 Nov.
Article
em En
| MEDLINE
| ID: mdl-11078982
ABSTRACT
OBJECTIVE:
Hyperinsulinemia in association with GH excess is considered a compensatory response to insulin resistance, but the possibility of alternative insulinotropic mechanisms has not been investigated in vivo. It is also unknown how GH influences the secretion from pancreatic beta-cells of amylin, a peptide which regulates prandial glucose homeostasis and may be linked to development of beta-cell dysfunction. We therefore measured plasma concentrations of two gut insulinotropic hormones, glucagon-like peptide 1 (GLP-1) and glucose-dependent insulin-releasing peptide (GIP), and total as well as non-glycosylated amylin, in 24 GH-deficient adults before and after 4 months of GH replacement (daily evening injections of 2 IU GH/m).DESIGN:
Double-blind, placebo-controlled, parallel study.METHODS:
All participants underwent an oral glucose tolerance test (OGTT) at 0 and 4 months.RESULTS:
A 33% suppression of fasting GLP-1 concentrations was measured in the GH group at 4 months (P=0.02), whereas a non-significant increase occurred in the placebo group (P=0.08). Fasting levels of GIP and amylin did not change significantly after 4 months in either group. The incremental response in GLP-1 during the OGTT was significantly lower after GH treatment as compared with both baseline (P=0.02) and the response in the placebo group (P=0. 03). The stimulation of GIP secretion following OGTT was similar on all occasions. The OGTT-induced incremental response in non-glycosylated amylin was moderately elevated after GH treatment as compared with placebo (P=0.05). Plasma concentrations of glucose and insulin, both in the fasting state and after the OGTT, were higher after GH treatment, but the ratio between amylin and insulin remained unchanged.CONCLUSIONS:
GH-induced hyperinsulinemia is accompanied by proportionate elevations in amylin concentrations and a blunting of gut GLP-1 secretion. The mechanisms underlying the suppression of GLP-1 remain to be elucidated.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fragmentos de Peptídeos
/
Hormônio do Crescimento
/
Hormônio do Crescimento Humano
/
Hormônios Gastrointestinais
/
Glucose
/
Amiloide
Tipo de estudo:
Clinical_trials
Limite:
Adult
/
Female
/
Humans
/
Male
Idioma:
En
Ano de publicação:
2000
Tipo de documento:
Article