ACCUMULATION OF TAURINE BY CULTURED RETINAL-PIGMENT EPITHELIUM OF RAT

  • 1 January 1977
    • journal article
    • research article
    • Vol. 16  (3) , 201-208
Abstract
Cultured rat retinal pigment epithelium actively accumulated taurine against a concentration gradient; an intracellular concentration of 12 mM was maintained at an extracellular taurine concentration of 0.12 mM. Taurine accumulation conformed to Michaelis-Menten kinetics for extracellular taurine concentrations between 0.006-0.05 mM; within that range the Km was 16 .mu.M and the Vmax was 2.3 nmol/h per .mu.l of cells. Above an extracellular concentration of 0.5 mM the kinetics were complex. Accumulation was inhibited by reduced temperature and iodoacetate and by dinitrophenol in the absence of glucose. Ouabain reduced extracellular Na+ and removal of extracellular K+ and Ca2+ also inhibited taurine accumulation. The cells also released previously accumulated taurine at a half-time of 1-3 h. The rapid accumulation and release of taurine by cultured retinal pigment epithelial cells is consistent with the idea that this tissue is a site for the transport of taurine in vivo.

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