Meeting Abstract
42.4 Monday, Jan. 5 High Fat Diet Increases Wheel Running in Mice Selectively Bred for High Voluntary Wheel Running MEEK, T.H.*; EISENMANN, J.C.; KEENEY, B.K.; HANNON, R.M.; GARLAND, T., Jr.; University of California, Riverside; Michigan State University; University of California, Riverside; University of California, Riverside; University of California, Riverside tmeek001@ucr.edu
Energy balance plays a key role in the ontogenetic development of many complex diseases, e.g., obesity, type II diabetes, and the metabolic syndrome. Mice from a long-term selection experiment for high voluntary wheel running offer a unique model to examine the contributions of genetic and environmental factors in determining relevant aspects of behavior and metabolism. Since generation 16 and continuing through 50, mice from the 4 replicate selected lines have been running 2.5-3-fold more revolutions/day as compared with 4 non-selected control lines, but the nature of this apparent selection limit is not yet understood. Wheel running, food consumption (Teklad Rodent Diet (W) 8604 or Harlan Teklad TD.88137 Western Diet, 42% kcal from fat), and body mass were measured regularly in 200 males for two months starting at weaning (21 days of age). As expected from previous studies of rodents, wheel access reduced body size (both mass and length). With body length as a covariate, ANCOVA indicated that the high-fat diet (HFD) increased body mass and retroperitoneal fat pad mass, but this effect was ameliorated by wheel access (diet * wheel access interaction P < 0.05). HFD had little or no effect on wheel running in control lines, but resulted in a nearly 50% increase in the selected lines. No other pharmacological or environmental agent has increased running to this extent in the selected lines. Future studies will be required to determine the mechanism of this remarkable stimulation, which may involve fuel usage during prolonged (~ 8 hours/day) endurance exercise and/or direct behavioral effects on motivation or the hypothesized "activitystat." Supported by Michigan State Univ. Seed Grant to JCE and NSF IOB-0543429 to TG.
