The relative level of metabolic activity in Gomori-positive (Gp) glia was estimated by comparing the incorporation rates of 3H-uridine, 3H-leucine and 3H-methionine into the nuclear macromolecules of the glia, neurons, ependyma and subcommissural organ (SCO). The uptake of 3H-uridine by Gp glia was somewhat lower than that by neurons and SCO but higher than that by ependyma. The incorporation of 3H-leucine was about the same in all studied types of cells, except for a lower uptake by ependyma. The rate of 3H-methionine incorporation into Gp glia and SCO was higher than that into neurons and ependyma. The neuron: Gp glia ratios obtained in the present study (0.9–1.4) are more or less within the range of the neuron: cerebral glia ratios reported by others for newly synthesized molecules of RNA and proteins. The results suggest that Gp glia have a relatively high metabolic activity as compared to that in neurons and perhaps SC