Figure 2: Effect of N,N,N,N-tetrakis-(2-pyridylmethyl) ethylenediamine (TPEN) in vivo on taurine levels in the rat retina. Taurine levels were determined by HPLC to 5 nM of the chelator and 5 days after injection io. Each value is the mean ± SEM, n = 4. * p 0.05 with respect to DMSO.