Relationship between growth hormone (GH) status, serum leptin and body composition in healthy and GH deficient elderly subjects.
AuthorsGill, M S
O'Neill, Paul A
Adams, J E
Thorner, M O
Shalet, Stephen M
Clayton, Peter E
AffiliationDepartment of Medicine, University of Manchester, UK.
MetadataShow full item record
AbstractOBJECTIVE: 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.
CitationRelationship between growth hormone (GH) status, serum leptin and body composition in healthy and GH deficient elderly subjects. 1997, 47 (2):161-7 Clin. Endocrinol.
- Serum leptin is increased in growth hormone-deficient adults: relationship to body composition and effects of placebo-controlled growth hormone therapy for 1 year.
- Authors: Fisker S, Vahl N, Hansen TB, Jørgensen JO, Hagen C, Orskov H, Christiansen JS
- Issue date: 1997 Jul
- Body composition in growth hormone deficient adults over the age of 60 years.
- Authors: Toogood AA, Adams JE, O'Neill PA, Shalet SM
- Issue date: 1996 Oct
- The effect of body composition on hexarelin-induced growth hormone release in normal elderly subjects.
- Authors: Rahim A, O'Neill P, Shalet SM
- Issue date: 1998 Nov
- Serum leptin and body composition in children with familial GH deficiency (GHD) due to a mutation in the growth hormone-releasing hormone (GHRH) receptor.
- Authors: de A Barretto ES, Gill MS, De Freitas ME, Magalhães MM, Souza AH, Aguiar-Oliveira MH, Clayton PE
- Issue date: 1999 Nov
- Low-dose growth hormone replacement lowers plasma leptin and fat stores without affecting body mass index in adults with growth hormone deficiency.
- Authors: Florkowski CM, Collier GR, Zimmet PZ, Livesey JH, Espiner EA, Donald RA
- Issue date: 1996 Dec