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Elevated leptin concentrations in growth hormone‐deficient hypopituitary adults[Note 1. Presented in part at the Society for Endocrinology winter ...]
Author(s) -
AlShoumer Kamal A. S.,
Anyaoku Victor,
Richmond William,
Johnston Desmond G.
Publication year - 1997
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1046/j.1365-2265.1997.2131054.x
Subject(s) - medicine , endocrinology , leptin , obesity , body mass index , hypopituitarism , insulin
BACKGROUND Hypopituitarism with growth hormone (GH) deficiency is associated with obesity characterized by central (abdominal) distribution of fat. Recent work has demonstrated that leptin, a product of obese gene, is raised in obesity. OBJECTIVE To study circulating leptin levels in GH‐deficient hypopituitary adults and to investigate its anthropometric, gender and metabolic relations. METHODS After an overnight fast of 10–12 hours, anthropometric parameters and body composition were measured and blood was collected for the measurement of circulating leptin, glucose, intact insulin, proinsulin, IGF‐I, total cholesterol, triglycerides, high density lipoprotein (HDL) cholesterol and low density lipoprotein (LDL) cholesterol. SUBJECTS Fifteen (7 men) GH‐deficient hypopituitary adults (maximum stimulated serum GH to provocative testing <6 mU/l) and 21 (10 men) normal control subjects matched for age, gender and body mass index (BMI). RESULTS Fasting serum leptin was significantly higher in hypopituitary patients than controls (12.0 ± 1.8 vs 8.0 ± 1.5 μg/l, P = 0.04). The increase was more marked in obese (BMI > 26.0 kg/m 2 ) patients compared with obese controls (15.3 ± 2.0 vs 8.8 ± 2.3 μg/l, P = 0.03) than in lean patients and controls. Obese control women and men had higher leptin levels than non‐obese (women, 16.6 ± 2.7 vs 8.6 ± 0.6 μg/l, P = 0.03; men, 4.9 ± 0.5 vs 2.9 ± 0.6 μg/l, P = 0.035). Similar changes were observed for obese versus non‐obese patients, although the changes did not reach statistical significance. Women in each group had significantly higher leptin concentrations than men (patients: 15.5 ± 2.3 vs 7.3 ± 1.4 μg/l, P = 0.009; controls: 12.6 ± 2.4 vs 4.3 ± 0.5 μg/l, P = 0.0001). These gender differences remained significant even when expressed in relation to BMI (patients: 0.57 ± 0.09 vs 0.26 ± 0.05 ng.m 2 /ml.kg, P = 0.009; controls: 0.43 ± 0.05 vs 0.16 ± 0.02 ng.m 2 /ml.kg, P = 0.0001). Serum leptin was positively associated with body mass index ( P = 0.003), percentage body fat mass ( P = 0.0001) and inversely related with age ( P = 0.043). It demonstrated no relation with body weight, waist circumference, waist to hip ratio, fasting IGF‐I, glucose, insulin, proinsulin, total cholesterol, triglycerides, HDL and LDL cholesterol in patients nor controls; 86% of variance in leptin was explained by a model including body mass index, gender, age and hypopituitarism. CONCLUSIONS Leptin concentrations are raised in GH‐deficient hypopituitary adults to a greater extent than would be expected from the degree of obesity.