Young adult male Wistar rats with an average initial weight of 250 gm were exercised from 5 to 8 weeks on a training regimen consisting of swimming one-half hour daily. Pair-fed, nonswimming animals served as controls. The unit protein of the heart ventricles and gastrocnemii (mg protein/gm wet weight of organ) was in general greater for the exercised animals. Aldolase activities were determined in the heart ventricles and the gastrocnemii. The results were expressed in terms of unit activities, actual total activities and relative total activities. The exercise significantly altered the unit and relative total activities of both the heart ventricles and skeletal muscle ( P < 0.05 or < 0.01), except for the 8th week in heart, and the actual total activities of the heart ( P < 0.01), except for the 8th week.
Fostering itself increases nicotine self-administration in young adult male rats