Lipoprotein lipase activity and lipolysis after swim training in obese Zucker rats

Obese and lean Zucker rats, 7 wk old, were swim trained or kept sedentary. Another group of obese rats was food restricted and exercised. Half the rats were killed after training for 8 wk, the remainder were retired and killed after an additional 8 wk. Neither treatment decreased adipocyte size in obese rats. Although basal lipolysis per cell was elevated in obese rats, their adipocytes were insensitive to epinephrine at 15 and 23 wk of age. Exercise training did not affect lipolysis. At all ages, adipose lipoprotein lipase (LPL) capacity was higher in obese relative to lean rats. In obese rats, swim training and exercise plus food restriction increased adipose and gastrocnemius LPL activity and depressed plasma insulin and triglyceride levels. All effects of exercise were transient. Thus, exercise training improved some of the metabolic disturbances in the Zucker obese rat but did not normalize adipocyte size, LPL activity, or lipolysis.