There are two parts to this project: 1. The role of cerebral glucose-6-phosphatase in sleep is under examination. The histidine phosphate of this enzyme-intermediate turns over more rapidly during sleep than in wakefulness. Studies on sugar transport and accumulation during sleep are under way, with particular attention to the possible role of Glc-6-Pase as an agent of transport. 2. We have isolated a sleep-promoting Factor S that accumulates during sleep deprivation. A double-labelingtechnique with C14 and H3 amino acids using sleeping and sleep-deprived cats allows us to purify this substance to homogeneity. Structural studies are in progress, and studies on the kinetics of accumulation are to be undertaken. The same substance has previously been obtained from goat brains in our laboratory. Sleep is monitored in rabbits electroencephalographicaly, and in rats by following nucturnal locomotor activity. BIBLIOGRAPHIC REFERENCES: Anchors, J.M., and Karnovsky, M.L.: Purification of cerebral glucose-6-phosphatase, An enzyme involved in sleep. J. Biol. Chem. 250: 6408-6416 (1975). Pappenheimer, J.R., Koski, G., Fencl, V., Karnovsky, M.L., and Krueger, J.: Extraction of sleep-promoting Factor S from cerebrospinal fluid and from brains of sleep-deprived animals. J. Neurophysiol. 38: 1299-1311 (1975).