Left ventricular atrial natriuretic factor-mRNA is altered by aging and exercise training of old F344 rats

LV ANF mRNA increases with aging in sedentary (SED) rats Exercise training (ET) can modulate gene expression altered with aging. We looked at ET on LV ANF-mRNA using male F344 rats and an ET protocol (treadmill exercise for 8-10 weeks at 60-70% max capacity). Results. Study one-Compared to 7-mo old SED, ANF mRNA increased (p<.01) in 15-mo old (+50%) and 25-mo old (+180%) SED rats. ET rats were killed 3-4 days after the last E bout. Compared to same aged SED rats, ANF-mRNA decreased (p<.05) in 25-mo old ET, but not in the 7- or 15-mo old ET. Values for 25-mo old ET were similar to the 15-mo old SED or ET groups. Study two compared 28-mo old SED and ET rats to 12-mo old SED. ET rats were killed right after E (E0) or 7 days later (E7). ANF-mRNA in 28-mo old SED was 3 fold higher than 12 mo old SED. However, ANF-mRNA in E0 group was identical to 12 mo SED while E7 was identical to 28 mo SED. Thus, the marked increase in LV ANF mRNA with old age can be decreased by ET to middle-age values, but reverts to old age values within one week after ET stops.