DNA content and distribution in supraoptic neuronal nuclei and in their satellites was studied in human subjects died under different conditions of hypothalamo-hypo-physeal neurosecretory activity: moderate (control) and high. In control observations, prevalence of diploid and paradiploid nuclei both in the secretory neurons and in the nuclei of glial satellites was noted. High neurosecretory activity was connected with a tendency towards increased DNA content in the neuronal nuclei, up to the appearance of some tetraploid elements. In the glial nuclei of the satellites, events of poliploidization were observed, that is, evidently, of adaptive character to maintain active functioning of the neurons under certain intensified conditions.