Voluntary running in male S5B/P1Ras rats fed high fat or high carbohydrate diets.

Nineteen week-old male S5B/P1Ras (S5B) rats were randomly assigned to one of 4 groups as follows: (a) activity wheel access (running)/high fat diet (RF); (b) no activity wheel access (non-running)/high fat diet (NRF); (c) activity wheel access (running)/high carbohydrate diet (RC); and (d) no activity wheel access (non-running)/high carbohydrate diet (NRC) for the seven weeks duration of the experiment. Throughout the 7 wk of the experiment, rats ran more during subsequent weeks than they did the previous week. RC rats ran more than RF rats as measured by the running slopes. All groups of rats lost weight at the initiation of the experiment but significantly more weight was lost by running rats than their nonrunning counterparts. The inguinal, epididymal and perirenal/retroperitoneal (P/R) fat depots weighed significantly less in the running than in the nonrunning groups. From among the 3 fat depots, the difference was greatest in the P/R depot. There were no diet or voluntary activity effects on plasma corticosterone concentrations except at week 2 when running rats had higher concentrations than nonrunning rats.