Interleukin-6 is not involved in appetite regulation following moderate-intensity exercise in males with normal weight and obesity.

Abstract

In obesogenic states and after exercise, interleukin (IL)-6 elevations are established, and IL-6 is speculated to be an appetite-regulating mechanism. This study examined the role of IL-6 on exercise-induced appetite regulation in sedentary normal weight (NW) males and those with obesity (OB). Nine NW participants and eight participants with OB completed one non-exercise control (CTRL) and one moderate-intensity continuous training (MICT; 60 minutes, 65% V̇O_2max ) session. IL-6, acylated ghrelin, active peptide tyrosine-tyrosine_3-36 , active glucagon-like peptide-1, and overall appetite perceptions were measured fasted, pre exercise, and 30, 90, and 150 minutes post exercise. Fasted IL-6 concentrations were elevated in OB (p = 0.005, <math xmlns="http://www.w3.org/1998/Math/MathML"> <mrow><msubsup><mi>η</mi> <mi>p</mi> <mn>2</mn></msubsup> </mrow> </math>  = 0.419); however, increases following exercise were similar between groups (p = 0.934, <math xmlns="http://www.w3.org/1998/Math/MathML"> <mrow><msubsup><mi>η</mi> <mi>p</mi> <mn>2</mn></msubsup> </mrow> </math>  = 0.000). Acylated ghrelin was lower in OB versus NW (p < 0.017, d > 0.84), and OB did not respond to MICT (p > 0.512, d < 0.44) although NW had a decrease versus CTRL (p < 0.034, d > 0.61). IL-6 did not moderate/mediate acylated ghrelin release after exercise (p > 0.251). There were no observable effects of MICT on tyrosine-tyrosine_3-36 , glucagon-like peptide-1, or overall appetite (p > 0.334, <math xmlns="http://www.w3.org/1998/Math/MathML"> <mrow><msubsup><mi>η</mi> <mi>p</mi> <mn>2</mn></msubsup> </mrow> </math>  < 0.062). These results suggest that IL-6 is not involved in exercise-induced appetite suppression. Despite blunted appetite-regulatory peptide responses to MICT in participants with OB, NW participants exhibited decreased acylated ghrelin; however, no differences in appetite perceptions existed between CTRL and MICT or NW and OB.