Apparent binding activity of [(3)H]glutathione in rat central and peripheral tissues

An apparent binding activity of [(3)H]glutathione (GSH) was detected in the synaptic membranous preparations obtained from the rat brain. Both methionine- and leucine-enkephalins exhibited a profound diminution of the apparent binding at 100 ?M in a naloxone-insensitive fashion. The retina was found to have the highest binding activity amongst various central structures examined, followed by the hypothalamus, striatum, spinal cord, midbrain, hippocampus, medulla-pons, cerebellum and cerebral cortex. In peripheral organs employed, the pituitary possessed an apparent binding activity higher than that in the retina, with progressively lower activities in the adrenal, liver, spleen, skeletal muscle and heart. No significant activity was detected in the kidney. These results suggest that specific binding sites of GSH may be located in the central and peripheral excitable tissues.