ABSTRACT. We looked at how zinc transporter 3 ZnT-3) mRNA expression in the rat retina is affected by low dietary zinc. Groups of 12 four-week-old male Sprague Dawley rats were fed on a low-zinc diet for 2, 4 or 6 weeks. Half of each group was then fed with a normal-zinc content diet and the other half was given a low-zinc content diet. The expression of ZnT-3, carbonic anhydrase 2 (CA2) and 14 (CA14) were detected by RT-PCR. After the rats were fed a low-zinc content diet for 2 weeks, their retina CA2 and CA14 mRNA levels were decreased, and the ZnT-3 mRNA was increased compared with the control rats. After they were fed a low-zinc diet for 4 weeks, ZnT-3, CA2 and CA14 mRNA levels decreased significantly. Then, after being changed back to a normal diet for 2 weeks, the rats had ZnT-3, CA2 and CA14 mRNA levels recovery in the retina.