Effects of zinc deficiency and supplementation on gene expression of bitter taste receptors (TAS2Rs) on the tongue in rats.

Abstract

We examined the effect of zinc deficiency and supplementation on the expression of bitter taste receptor (TAS2R) and epithelial sodium ion channel (ENaC) genes on the tongue in rats. Prospective animal study. A total of 36 male Sprague-Dawley rats (3 weeks old) were used. Twelve rats were fed a normal diet for 28 (n = 6) or 56 (n = 6) days, another 12 were fed a zinc-deficient diet for the same periods, and still another 12 were fed a zinc-deficient diet for 28 days and then administered zinc for a further 28 days. The epithelium of the circumvallate papillae was collected, and expression of the TAS2R40, TAS2R105, TAS2R107, TAS2R118, TAS2R121, TAS2R136, TAS2R140, and ENaC genes was examined by reverse transcriptase-polymerase chain reaction. Gene expression frequency of TAS2R40 and TAS2R107 significantly decreased in rats fed a zinc-deficient diet, and frequency of TAS2R107 significantly increased following zinc administration. No changes were noted in expression of TAS2R105, TAS2R118, TAS2R121, or ENaC in zinc-deficient rats. Our findings suggest that zinc may affect gene expression for some TAS2Rs on the tongue in rats.