Related Experiment Videos
Exercise training down-regulates ob gene expression in the genetically obese SHHF/Mcc-fa(cp) rat
J E Friedman1, C M Ferrara, K S Aulak
1Department of Nutrition, Case Western Reserve University School of Medicine, Cleveland, OH 44106-4935, USA.
Hormone and Metabolic Research = Hormon- Und Stoffwechselforschung = Hormones Et Metabolisme
|May 1, 1997
Summary
Exercise training reduces body fat and obesity gene (ob) mRNA levels in both lean and obese rats. This supports a feedback loop regulating body weight through energy expenditure.
Area of Science:
- Metabolic research
- Obesity research
- Exercise physiology
Background:
- The obesity gene (ob) encodes leptin, a hormone from adipose tissue that regulates appetite and energy expenditure.
- Increased ob mRNA levels in obesity suggest potential leptin resistance.
- Rodent models of obesity, insulin resistance, and type II diabetes are crucial for studying these mechanisms.
Purpose of the Study:
- To investigate the effects of exercise training on ob mRNA gene expression and body composition in obese rats.
- To determine if increased energy expenditure influences the feedback loop between adipose tissue and the hypothalamus.
Main Methods:
- Six-week-old lean and obese SHHF/Mc-fa(cp) rats underwent treadmill training for 8-12 weeks.
- Exercise involved running at 70% peak oxygen uptake, 5 days/week, for 1.5 hours/day.
- Body composition and ob mRNA levels in adipose tissue were measured post-training.
Main Results:
- Exercise training significantly reduced total body fat in both lean and obese rats, without affecting body weight.
- Obese rats showed a four-fold increase in subcutaneous ob mRNA compared to lean controls.
- Exercise training decreased ob mRNA by 85% in lean rats and 50% in obese rats compared to their respective sedentary controls.
Conclusions:
- Exercise training effectively reduces fat mass and ob mRNA expression in both lean and obese rats.
- These findings support a hypothalamic-adipocyte feedback loop that regulates body weight by modulating ob gene expression in response to energy expenditure.