Introduction. Mouse studies suggest that exercise can promote white adipocyte browning by increasing the expression of UCP1, a gene that encodes the protein responsible for non-shivering thermogenesis. In humans, however, there is limited evidence that exercise can promote UCP1 expression in white adipocytes. The aim of this study was therefore to use a novel human serum on human white adipocyte assay to study the effects of exercise on UCP1 expression in white adipocytes. Method. To study exercise-induced browning of primary human subcutaneous white adipocytes, we obtained whole blood samples from 7 untrained controls, 9 natural bodybuilders, 8 sprinters, and 11 endurance athletes at fasted rest and after a graded cycle ergometry test to subjective exhaustion. From whole-blood, we generated serum which we used at a 10% v/v dilution to treat differentiated, primary human subcutaneous white adipocytes (purchased from Zen-Bio) for 16 h. We then isolated total RNA with Trizol and measured UCP1 mRNA by RT-qPCR.Results. In untrained controls, exercise-conditioned sera increased UCP1 expression significantly by 40% when compared to resting sera. In contrast, the exercise-conditioned sera of natural bodybuilders, sprinters and endurance athletes increase UCP1 expression by 124%, 185%, and 112%, respectively. Despite the mean increase, individual athlete responses included non-responders, average responders, and superresponders in all athlete groups. Discussion. In this study, we report a novel, minimally invasive human serum on human white adipocyte assay to assess white adipocyte browning (i.e. UCP1 expression). Using this assay to study the effect of exercise on browning revealed that exercise increased mean UCP1 expression in all groups. Some athletes were super-responders as their post exercise sera increased UCP1 expression by more than 200% when compared to sera taken at rest.     «

Introduction. Mouse studies suggest that exercise can promote white adipocyte browning by increasing the expression of UCP1, a gene that encodes the protein responsible for non-shivering thermogenesis. In humans, however, there is limited evidence that exercise can promote UCP1 expression in white adipocytes. The aim of this study was therefore to use a novel human serum on human white adipocyte assay to study the effects of exercise on UCP1 expression in white adipocytes. Method. To study exerc...     »