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

Objectives/Hypothesis: 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. Study Design: Prospective animal study. Methods: 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. Results: 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. Conclusions: Our findings suggest that zinc may affect gene expression for some TAS2Rs on the tongue in rats. Laryngoscope, 2012