RETINAL-PIGMENT EPITHELIUM CELL-CULTURE AS A MODEL FOR EVALUATION OF THE TOXICITY OF TAMOXIFEN AND CHLOROQUINE

The retinal pigment epithelium (RPE) removes the outer segments of pho toreceptor cells by phagocytosis. We studied the effects of tamoxifen and chloroquine on the activity of the lysosomal enzymes N-acetyl-beta -glucosaminidase and cathepsin D in RPE in vitro to evaluate the possi ble eye toxicity caused by these drugs. The results show decreases in the activities of lysosomal enzymes after drug exposure. The enzymes t ested seemed to be more sensitive to tamoxifen than to chloroquine. A profound decrease in the activities of the lysosomal enzymes only star ted at concentrations above therapeutic dose levels.