Assessment of GH/IGF-I axis in obesity by evaluation of IGF-I levels and the GH response to GHRH plus arginine test

被引:28
作者
Maccario, M [1 ]
Gauna, C [1 ]
Procopio, M [1 ]
Di Vito, L [1 ]
Rossetto, R [1 ]
Oleandri, SE [1 ]
Grottoli, S [1 ]
Ganzaroli, C [1 ]
Aimaretti, G [1 ]
Ghigo, E [1 ]
机构
[1] Univ Turin, Div Endocrinol, Dipartimento Med Interna, Turin, Italy
关键词
GH; IGF-I; obesity; GH insufficiency; GHRH; arginine;
D O I
10.1007/BF03343585
中图分类号
R5 [内科学];
学科分类号
1002 ; 100201 ;
摘要
The GH response to provocative stimuli in obese is often as low as in panhypopituitaric patients with severe GHD; however, IGF-I levels are normal or slightly reduced. In 53 patients with simple obesity (11 M and 42 F, age: 40.3+/-1.6 yr, BMI: 39.1+/-1.0 Kg/m(2)), we evaluated the GH response to GHRH (1 mu g/kg iv)+arginine (ARG, 0.5 g/kg iv), and total IGF-I levels. The mean (+/-SE) GH peak after GHRH+ARG was markedly lower (74% reduction, p<0.0001) in obese (16.8+/-2.0 mu g/l) than in normal subjects (62.7+/-4.3 mu g/l). IGF-I levels in obese patients (134.0+/-7.6 mu g/l) were lower (33% reduction, p<0.001) than in normal subjects (200.8+/-5.7 mu g/l). Taking into account the 3(rd) centile limit of normal response, the GH response to GHRH+ARG was reduced in 62.3% (33/53) of the obese patients, and 21.2% (7/33) of them had low IGF-I levels. Assuming the 1(st) centile limit, it was reduced in 33.9% (18/53) obese subjects, and 22% (4/18) of them had low IGF-I levels. Considering 3.0 mu g/L as arbitrary cut-off, the GH response was reduced in 5.7% (3/53) of the obese patients, and still one of them had low IGF-I levels. Our findings: a) confirm that the secretory capacity of somatotroph cells is often deeply impaired in obesity; b) demonstrate that IGF-I assay generally rules out severe impairment of GH/IGF-I axis in obese patients with marked reduction of the GH secretion; c) indicate that the percentage of obese patients with concomitant reduction of GH secretion and ICF-I levels is not negligible. Thus, IGF-I assay should be routinely performed in obese patients; those presenting with low IGF-I levels should undergo further evaluation of their hypothalamo-pituitary function and morphology, particularly in the presence of empty sella. (C) 1999, Editrice Kurtis.
引用
收藏
页码:424 / 429
页数:6
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