Poster Presentation Australian & New Zealand Obesity Society Annual Scientific Meeting 2013

Energy and appetite regulating hormones: Sex and weight category differences prior to weight loss (#217)

Robin Callister 1 , Rebecca Williams 1 , Lisa Wood 1 , Philip Morgan 1 , Clare Collins 1
  1. University of Newcastle, Callaghan, NSW, Australia

Background: Energy and appetite regulating hormones have been proposed as playing a role in overweight and obesity and preliminary studies suggest a number of these differ between males and females. Aim: To compare the concentrations of leptin, ghrelin and adiponectin in overweight and obese males and females. Methods: Blood samples from a subsample of overweight (BMI 25-29.9 kgm-2) or obese (BMI 30-40 kgm-2) men (n=25) and women (n=35) aged >18 years enrolled in an online weight loss RCT1 were used. Baseline blood samples were drawn after an overnight fast and stored at -80°. Concentrations of leptin, ghrelin (acylated and unacylated) and adiponectin were determined by enzyme-linked immunosorbent assay. Results: There were no sex differences in age (M 41.8±11.3 vs F 41.3±10.7 y) or BMI (M 31.6 ±3.4 vs F 32.4±4.0 kg.m-2). Concentrations of leptin, unacylated ghrelin and adiponectin were all significantly higher in females than males (leptin: p<0.001; unacylated ghrelin: p=0.022; adiponectin: p=0.016). In the overweight category, females had significantly higher concentrations of leptin (pg/mL [p<0.001] and per kg/bw [p<0.001]) and acylated ghrelin (per kg/bw [p<0.007]) than males. In the obese, females had significantly higher concentrations of leptin (pg/mL [p<0.001] and per kg/bw [p<0.001]), unacylated ghrelin (pg/mL [p<0.014] and per kg/bw [p<0.010]) and adiponectin (ng/mL [p<0.020] and per kg/bw [p<0.009]) than males. Obese females had higher concentrations of leptin (pg/mL [p<0.0285]) and lower concentrations of acylated ghrelin (pg/mL [p<0.0230] and per kg/bw [p<0.0036]) and unacylated ghrelin (per kg/bw [p<0.0396]) compared with those classed as overweight. Obese males had higher concentrations of leptin (pg/mL [p<0.0305]) and lower concentrations of unacylated ghrelin (per kg/bw [p<0.0229]) than those in the overweight category. Conclusion: There are differences between males and females in concentrations of appetite and energy regulating hormones. The importance of these differences in achieving weight loss success warrants further investigation.