Taurine levels, uptake and synthesizing enzyme activities in degenerated rat retinas.

Taurine levels, cysteine oxidase and cysteine sulfinate decarboxylase activities, [³⁵S]-taurine uptake in vitro and [³⁵S]taurine accumulation in vivo were studied in the retinas of rats in which the inner or the outer cell layers were degenerated by treatment with monosodium glutamate or with iodoacetate-malate respectively.Monosodium glutamate treatment significantly reduced the cysteine oxidase activity to 12% of control and the cysteine sulfinate decarboxylase activity to 34% of control. Taurine levels were unaffected. Taurine accumulation was slightly decreased and taurine uptake in vitro was unchanged by MSG treatment.Iodoacetate-malate treatment decreased taurine levels to 75% of control and the activities of cysteine oxidase and cysteine sulfinate decarboxylase to 73 and 60% of control, respectively. Iodoacetate-malate treatment decreased taurine accumulation in vivo to only 12% of control; taurine uptake in vitro was also reduced to approximately 50% of control.