Cerebral lysosomes. IV. The regional and intracellular distribution of arylsulfatase and evidence for two populations of lysosomes in rat brain

Abstract

1. 1. The activities of arylsulfatase and were determined in 6 regions of rat brain.2. 2. The degree of structural latency of the two hydrolases was estimated.3. 3. The intracellular distribution of arylsulfatase was studied in the cortex, thalamus and striatum and a lysosomal localization could be established.4. 4. Centrifugation of the cortical crude lysosomal fraction on continuous sucrose density gradients revealed the existence of a minority population of lysosomes which, unlike the bulk, sedimented through the gradient and could be recovered in pellet form. Proportionately more sulfatase than glucosaminidase was found in this lysosomal population.5. 5. The main lysosomal population was well separated from mitochondria but was contaminated by the membranes bearing acetylcholine esterase and soluble lactic dehydrogenase. The pellet fraction was virtually free of contamination.6. 6. Evidence for the presence of more than one population of lysosomes in the thalamus and the hypothalamus of rat brain was also obtained.