Endocrine Abstracts

Introduction: Adipocytokines secreted by adipose tissue are suggested to play a role in the development of obesity-related complications. Leptin is mainly produced and secreted by adipose tissue and appears as an important regulator of energy balance. The relationship between leptin levels and energy expenditure remain unclear. Energy expenditure related to physical activity (PA) is the most variable part of total energy expenditure. There is some evidence that the habitual level of PA may be a significant determinant of leptin concentrations, but the scarce document in leptin gene expression. The aim of this study was to investigate the association between habitual PA and the leptin gene expression among non-diabetic adults.

Materials and methods: Visceral and subcutaneous adipose tissues were gathered from 98 non-diabetic participants aged ≥20, who had undergone elective abdominal surgery. Physical activity was collected using a valid and reliable International Physical Activity Questionnaire (IPAQ)-long form, and the metabolic equivalent of task (MET) was calculated. Respondents were asked to report time spent in PA performed across leisure time, work, domestic activities, and transport at each of 3 intensities: walking, moderate, and vigorous. The mRNA expressions of leptin gene in visceral and subcutaneous adipose tissues were analyzed by Real-Time PCR.

Findings: The mean age of participants (22.7% male) were 41.7 years. No significant difference was observed for leptin gene expression in subcutaneous (−0.135 vs. 0.791, P=0.992) and visceral (−1.582 vs 0.915, P=0.891) fat mass between non-obese (BMI <30 kg/m²) and obese (BMI ≥30 kg/m²) participants, respectively. After controlling for total energy intake, BMI, and insulin level, total MET (β=−0.428, P<0.001) was negatively associated with leptin gene expression in visceral adipose tissue among obese participants; however total MET was not significantly related to leptin gene expression in subcutaneous adipose tissue. Besides, MET related home (β=−0.316, P=0.035) and leisure time (β=−0.651, P<0.001) were negatively associated with visceral adipose tissue leptin gene expression.

Conclusions: Physical activity is negatively related to leptin gene expression in visceral adipose tissue participants with obesity only and this association is independent of fasting plasma insulin. This finding exaggerated the crucial role of PA to control of the development of obesity.