Exercise training decreases in vitro stimulated lipolysis in a visceral (mesenteric) but not in the retroperitoneal fat depot of high-fat-fed rats.

The purpose of the present study was to determine the effects of an exercise training programme in high-fat-fed rats on in vitro lipolysis in a visceral (mesenteric) and a non-visceral fat depot (retroperitoneal) and its relationship to perilipin content. Two groups of female rats were fed a high-fat diet (42 % as energy) for 8 weeks, one remaining sedentary (Sed) and the other being exercise trained (Tr) for this entire period. Rats were killed after 2 and 8 weeks of their respective treatment. The significantly (P < 0.01) higher levels in mesenteric and retroperitoneal fat pad weights, plasma leptin, NEFA and glucose observed with time in Sed high-fat-fed rats were significantly (P < 0.05) attenuated in Tr animals. Isoproterenol-stimulated (10- 5-10- 4 m) lipolysis in the mesenteric, but not in the retroperitoneal tissue, was significantly (P < 0.05) lower (about 57 %) in Tr than in Sed rats after 8 weeks of high-fat feeding. The isoproterenol-stimulated lipolysis in the mesenteric tissue of 8-week Tr high-fat-fed rats was lowered to the level measured in 2-week fat-fed rats although mesenteric fat accumulation was still significantly (P < 0.01) higher in 8- than in 2-week Tr rats. Perilipin content (Western blot) was not affected by the exercise training programme. These results indicate that exercise training resulted in a reduction in the high-fat diet-induced elevated levels of lipolysis in the mesenteric tissue. This response appears to be independent of the perilipin content.