The influence of lithium and/or selenium on plasma amino acids profile in rats

Selenium belongs to essential microelements and is used in agriculture. Lithium is used in medicine and the possibility of its exposure by environmental pollution has been reported. Both elements have been found to be connected with amino acids metabolism.

The aim of the study was to compare the effect of lithium and selenium on plasma amino acids in rats, and to evaluate the influence of selenium in organisms exposed to lithium.

The effect of selenium (0.5 mg/kg b.w., orally as Na₂SeO₃) and/or lithium (2.7 mg/kg b.w., orally as Li₂CO₃) given for 6 weeks on the plasma profile of selected amino acids in rats was studied. The concentrations of amino acids were determined using ion exchange chromatography with the aid of an amino acids analyzer AAA400.

A significant effect of lithium on plasma amino acids profile was found in rats, much greater than for selenium. Selenium treatment slightly increased Tau, Phe, Tyr, Ala, Trp, Ser and Gln, while Lys and Orn were enhanced in a significant way. In contrast, Li-treatment caused a well-marked increase in Phe, Orn, Ala, His, Trp, Asp and Gln, whereas all the others were only slightly increased. Co-treatment resulted in a significant increase in Orn and Trp, a slight enhancement of Phe, Lys and His, while the rest remained unchanged.

A significant effect of lithium alone on plasma amino acids profile in animals was demonstrated, with a much less influence of selenium alone. Co-treatment generally resulted in a slight or no effect. The slight selenium influence seems important regarding its agricultural application and the growing interest in its supplementation. Results concerning lithium could contribute to the research regarding the mechanism of Li action.