Objective: To study effects and regulatory mechanism of zinc on cold stress in rats.
Methods: Sixty male SD rats were randomized into 4 groups. Rats of group I and III drank tap water, group II and IV drank high-zinc water[1 mg/(kg.d)], respectively, and 5 days later, rats from group III and IV underwent exposure to cold-15 degrees C for 2 hours. The rectal temperature before and after cold exposure were assayed. Zinc concentration in plasma and tissue were assayed. Radioactivity was measured by liquid glimmer instrument using 3H-GTP binded UCPin mitochondria. The dissociation constant(Kd) and maximal binding(Bmax) was determined from Scathardplot.
Results: The decreased range of rectal temperature during cold exposure of group zinc and control were -2.95 +/- 0.61 and -1.16 +/- 0.39(P < 0.05), respectively. There was a significant increase in the content of zinc in the tissue after cold exposure. With zinc and cold treatment, Bmax increased, Kd remained unchanged.
Conclusion: Zinc might play an important role in cold stress and cold endurance through increase concentration of UCP in brown adipose tissue mitochondria.