Effects of exercise on plasma adiponectin levels in athletes

Abstract

Adipose tissue is an endocrine organ which releases biologically active adipokines. Adiponectin, an adipocyte-derived protein structurally similar to complement 1q, plays a significant role in metabolic disorders, due to its insulin sensitizing, anti-inflammatory and anti-atherogenic properties. AdipoR 1 and AdipoR 2 , mediate the metabolic actions of adiponectin by activating adenosine monophosphate-activated protein kinase (AMPK) and peroxisome proliferator-activated receptors-alpha (PPAR-α) which leads to an increase in fatty acid combustion and energy consumption, fatty acid oxidation and glucose uptake in myocytes and reduces gluconeogenesis and thus leads to increased insulin sensitivity. Plasma adiponectin level is affected by multiple factors: gender (females have higher plasma adiponectin levels), obesity-linked diseases (metabolic syndrom, diabetes mellitus type 2 and atherosclerosis are associated with lower adiponectin levels), lifestyle -including exercise. Yet, to date, little is known about the response of adiponectin concentrations to exercise and, in particular, the response of this hormone to training in population of athletes. The aim of this review is to overview the published evidence for the effects of exercise on adiponectin levels in athletes. Adiponectin concentration presents a delayed increase (30 min) after short-term intense performance, by athletes, both male and female. It seems that adiponectin concentrations do not change in response to long-term exercise. No significant difference was found in total adiponectin and/or high-molecular weight (HMW) oligomers in long-term effects of high physical training in athletes. Adiponectin can serve to monitor training loads and the establishment of individual limit values of training loads. Further studies are needed to clarify possible mechanisms by which adiponectin might influence energy homeostasis during heavy training in elite athletes. Key words: adiponectin, adipose tissue, athlets, exercise. SažetakMasno tkivo je endokrini organ, koji oslobađa biološki aktivne adipokine. Jedan od adipokina je adiponektin, protein strukturno sličan komplementu 1q, koji ima značajnu ulogu u metaboličkim poremećajima zbog antiinflamatornog dejstva, anti-aterogenih svojstava i dejstva na insulin. Receptori AdipoR 1 i AdipoR 2 posreduju metaboličko dejstvo adiponektina aktiviranjem adenozin-monofosfat aktivirane proteinkinaze (AMPK) i peroksizom proliferator aktiviranog receptora alfa (PPAR-α), što dovodi do povećanog katabolizma i oksidacije masnih kiselina, preuzimanja glukoze u miocitima, smanjenja glukoneogeneze i povećanja osetljivosti na insulin. Na nivoe adiponektina utiče više činilaca: pol (žene imaju više vrednosti adiponektina u plazmi), bolesti povezane sa gojaznošću (metabolički sindrom, tip 2 dijabetesa melitusa i ateroskleroza su povezane sa nižim vrednostima adiponektina) i način života (uključujući vežbanje). Do danas se ipak malo zna o uticaju rekretivnog vežbanja na nivoe adiponektina, a posebno o uticaju treninga na nivo adipo...