Studies on synthesis and uptake of taurine in rat lens in vitro

The occurrence of large taurine pool sizes in the crystalline lens was further elucidated by studying the in vitro synthesis and uptake of taurine in the rat lens. It was observed that a time- and concentration-dependent synthesis of taurine from methionine occurred in the rat lens. The time curve for uptake was linear up to 4 hr and was not saturated up to 40 mM concentration of taurine. The uptake was inhibited by ouabain, cyanide, Ca2+, GTP and cGMP but was not affected by ATP and cAMP. It is suggested that a dual mechanism exists for maintenance of high concentrations of taurine in the lens. Moreover, the uptake mechanism is energy-dependent.