Effects of exercise training on regional adipose tissue metabolism in pregnant rats.

To investigate the effects of intense exercise training on maternal adiposity and fetal development, normal lean Zucker (Fa/Fa) rats were divided into three groups: control nonpregnant (CNP), control pregnant (CP), and exercise-trained pregnant (TRP). Trained rats swam three continuous hours per day, 6 days/wk, throughout pregnancy. Food efficiency increased with pregnancy, the highest values being observed during the last trimester of the gestation period. On day 21, pup number, weight, and body composition were similar for CP and TRP. By day 21 of gestation, in both TRP and CP rats, inguinal adipose tissue weight, cell size, and lipoprotein lipase (LPL) activity increased; although TRP values were smaller (P less than 0.05). In CP rats, parametrial and retroperitoneal adipose tissue weights, cell size, and LPL activities increased throughout pregnancy, whereas TRP values were similar to CNP (P less than 0.05). Parametrial fat cell lipolysis showed, however, no effect of training. These results indicate that the extensive energy expenditure occurring during endurance training selectively reduced the dams' adiposity in a regionally specific fashion without any apparent alteration in pup development. The increased substrate utilization required by training during pregnancy did not, however, modify fat cell lipolysis but rather prevented lipid filling through suppression of LPL activity of some depots.