Effects of zinc deficiency and supplementation on the glycogen contents of liver and plasma lactate and leptin levels of rats performing acute exercise

The aim of the present study was to investigate how zinc (Zn) deficiency and supplementation affect glycogen content of the liver and plasma lactate and leptin levels of rats performing acute swimming exercise just before the blood samples were obtained. Four sets of 10 rats each served as the (1) Zn-deficient group, (2) Zn-supplemented group, (3) swimming controls, and (4) normal controls. Plasma lactate levels of Zn-deficient animals were significantly higher than those in the other three groups (p < 0.01), and those in the swimming controls (group 3) were significantly higher than in the Zn-supplemented animals, group 2 (p < 0.01). The plasma glucose of the Zn-deficient group was significantly higher than all other groups (p < 0.01) and that of group 2 was significantly lower than group 4 (p < 0.01). Glycogen levels in liver of the Zn-deficient animals was significantly lower than groups 2 and 4 (p < 0.01), and, in turn, were higher than for group 3 (p < 0.01). The plasma leptin and Zn levels of group 1 were significantly lower than in all other groups (p < 0.01). These results suggest that Zn deficiency exerts a negative influence in the above-mentioned parameters and that Zn supplementation has the opposite effect.