Iron and Zinc homeostasis in female rats with physically active and sedentary lifestyles
To determine the effects of repeated physical activity on iron and zinc homeostasis, we quantified blood and tissue levels of these two metals in sedentary and active Long-Evans rats housed in cages without and with running wheels, respectively, from post-natal day (PND) 22 to 100. The 22-day old active rats housed in cages with running wheels increased their use on the wheel each day for about 38 days, running primarily at night. At PND 100, there were no differences in red blood cell count and hemoglobin between the two groups but hematocrit was significantly decreased in the active animals relative to the sedentary animals. The concentrations of both non-heme iron and zine in plasma were significantly decreased among the active relative to the sedentary animals. Plasma concentrations of the metal storage protein ferritin were also diminished among the active relative to the sedentary rats. In the lung, both metals were increased in concentration among the active animals but the change in zinc did not reach significance. Similarly, tissue non-heme iron and zinc levels were both increased in heart and muscle from the active group. It is concluded that repeated physical activity can impact iron and zinc homeostasis with decreased concentrations of both metals in the plasma and liver and increased levels in the lung, heart, and skeletal muscle.