Effect of combined administration of growth hormone (GH)-releasing hormone, GH-releasing peptide-6, and pyridostigmine in normal and obese subjects

Metabolism ◽  
1995 ◽  
Vol 44 (6) ◽  
pp. 745-748 ◽  
Author(s):  
F. Cordido ◽  
A. Peñalva ◽  
R. Peino ◽  
F.F. Casanueva ◽  
C. Dieguez
1990 ◽  
Vol 122 (3) ◽  
pp. 385-390 ◽  
Author(s):  
R. C. Castro ◽  
J. G. H. Vieira ◽  
A. R. Chacra ◽  
G. M. Besser ◽  
A. B. Grossman ◽  
...  

Abstract Obese patients are characterised by several neuroendocrine abnormalities, including characteristically a decrease in growth hormone responsiveness to GH-releasing hormone. In normal subjects, the GH response to GHRH is enhanced by the acetylcholinesterase inhibitor, pyridostigmine. We have studied the effect of this drug on GH secretion in gross obesity. Twelve obese patients were studied (mean weight 156% of ideal) and compared with a group of 8 normal volunteers. Each subject was initially studied on two occasions, in random order, with GHRH (1–29) NH2 100 μg iv alone and following pretreatment with pyridostigmine 120 mg orally one hour prior to GHRH. In obese patients, the GH response to GHRH was significantly blunted when compared to controls (GH peak: 20 ± 4 vs 44 ± 16 μg/l; mean ± sem). After pyridostigmine, the response to GHRH was enhanced in the obese subjects, but remained significantly reduced compared to non-obese subjects treated with GHRH and pyridostigmine (GH peak: 30 ± 5 vs 77 ± 20 μg/l, respectively). In 6 subjects, higher doses of GHRH or pyridostigmine did not further increase GH responsiveness in obese patients. Our results suggest that obese patients have a disturbed cholinergic control of GH release, probably resulting from increased somatostatinergic tone. This disturbed regulation may be responsible, at least in part, for the blunted GH responses to provocative stimuli.


Metabolism ◽  
1999 ◽  
Vol 48 (9) ◽  
pp. 1152-1156 ◽  
Author(s):  
Roberto Lanzi ◽  
Livio Luzi ◽  
Andrea Caumo ◽  
Anna Claudia Andreotti ◽  
Marco Federico Manzoni ◽  
...  

1990 ◽  
Vol 71 (6) ◽  
pp. 1481-1485 ◽  
Author(s):  
EZIO GHIGO ◽  
STEFANIA GOFFI ◽  
MARIO NICOLOSI ◽  
EMANUELA ARVAT ◽  
FRANCESCA VALENTE ◽  
...  

1995 ◽  
Vol 132 (6) ◽  
pp. 712-715 ◽  
Author(s):  
A Leal-Cerro ◽  
E Garcia ◽  
R Astorga ◽  
FF Casanueva ◽  
C Dieguez

Leal-Cerro A, Garcia E, Astorga R, Casanueva FF, Dieguez C. Growth hormone (GH) responses to the combined administration of GH-releasing hormone plus GH-releasing peptide 6 in adults with GH deficiency. Eur J Endocrinol 1995;132:712–5. ISSN 0804–4643 In recent years the health problems of adults with growth hormone deficiency (GHD) and the benefits of GH replacement therapy have received considerable attention. However, the reliability of conventional GH tests in the assessment of pituitary GH reserve in this group of patients is still controversial. In this study, we assessed GH secretion after the combined administration of GH-releasing hormone (GHRH) (1 μg/kg iv) and GH-releasing peptide 6 (GHRP-6, 1 μg/kg iv) in adult patients diagnosed with GHD by conventional GH testing, and correlate this response with insulin-like growth factor I levels. Twenty-one subjects (13 male, 8 female) with long-standing diagnosis of GHD aged 21–54 years were studied. In 13 subjects GH responses to GHRH plus GHRP-6 were markedly reduced (peak GH response <10 mU/I), whereas in the remaining eight the response was greater (range 11–100 mU/l), In conclusion, our data show that combined administration of GHRH plus GHRP-6 elicited a significant increase in plasma GH levels in about 40% of patients diagnosed with GHD by conventional GH testing. C Dieguez, PO Box 563, 15700 Santiago de Compostela, Spain


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