Document Detail


Relationship between growth hormone (GH) status, serum leptin and body composition in healthy and GH deficient elderly subjects.
MedLine Citation:
PMID:  9302388     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVE: Growth hormone (GH) secretion declines with age and is affected by body composition. The signal that mediates the latter relationship remains III-defined. Leptin, the protein product of the adipocyte specific ob gene, is thought to accurately reflect fat mass and could therefore be a candidate to influence GH secretion. We have therefore investigated the relationship between GH status, leptin and body composition in normal and GH-deficient elderly subjects. DESIGN: GH Secretion was assessed by 20-minute sampling over 24 hours and serum leptin concentrations were measured in a single morning, fasted sample. PATIENTS: Twenty-one GH deficient elderly patients (61-83 years) and 22 gender- and BMI-matched controls (61-88 years). MEASUREMENTS: Body composition was assessed by dual-energy X-ray absorptiometry (DEXA). GH was measured in an ultrasensitive chemiluminescent assay and serum leptin was determined by radio-immunoassay. RESULTS: Leptin was correlated with percentage body fat in both sexes (male r = 0.75, female r = 0.89, both P < 0.001). Male patients had increased fat mass (FM) (P < 0.01) and leptin concentrations (P < 0.05) but similar lean mass (LM) compared with controls. However, leptin concentration per unit FM was identical in both groups (P = 0.3). In contrast, female patients had lower LM (P < 0.05) but similar FM to controls, yet their leptin concentration per unit FM was twice that of the controls (P < 0.05). In multiple linear regression (MLR) leptin was determined positively by FM and negatively by LM (controls r2 = 76%; patients r2 = 73%, both P < 0.0001). When controlled for gender, GH secretion in the controls was correlated negatively with leptin (r = -0.68, P < 0.01) and negatively with percentage body fat (r = -0.73, P < 0.01). In MLR, using leptin as a marker of body composition, 66% of the variability in GH secretion in the controls could be explained by gender (38%) and by leptin (28%). CONCLUSIONS: Both decreased lean mass and increased fat mass raise serum leptin concentrations in normal and growth hormone-deficient elderly subjects. Leptin is therefore a marker of body composition rather than fat mass alone. The influence of body composition on growth hormone secretion in the elderly may be mediated through leptin, acting as a peripheral signal from adipose tissue to decrease GH secretion.
Authors:
M S Gill; A A Toogood; P A O'Neill; J E Adams; M O Thorner; S M Shalet; P E Clayton
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Clinical endocrinology     Volume:  47     ISSN:  0300-0664     ISO Abbreviation:  Clin. Endocrinol. (Oxf)     Publication Date:  1997 Aug 
Date Detail:
Created Date:  1997-10-16     Completed Date:  1997-10-16     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0346653     Medline TA:  Clin Endocrinol (Oxf)     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  161-7     Citation Subset:  IM    
Affiliation:
Department of Medicine, University of Manchester, UK.
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MeSH Terms
Descriptor/Qualifier:
Absorptiometry, Photon
Aged
Aged, 80 and over
Body Composition / physiology*
Cohort Studies
Female
Growth Hormone / blood,  deficiency*
Humans
Leptin
Male
Middle Aged
Proteins / metabolism*
Regression Analysis
Sex Factors
Grant Support
ID/Acronym/Agency:
DK 32632/DK/NIDDK NIH HHS; RR 00847/RR/NCRR NIH HHS
Chemical
Reg. No./Substance:
0/Leptin; 0/Proteins; 9002-72-6/Growth Hormone
Comments/Corrections
Comment In:
Clin Endocrinol (Oxf). 1997 Aug;47(2):169-71   [PMID:  9302389 ]

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