Effect of diencephalic stimuli on 17-hydroxycorticosteroid secretion in unanesthetized dogs

¹ Worcester Foundation for Experimental Biology, Shrewsbury; and Dementia Praecox Research Project, Worcester State Hospital, Worcester, Massachusetts

In unanesthetized dogs, adrenal venous blood was collected and its plasma content of 17-hydroxycorticosteroids (17-OHCS) estimated. Electrodes were implanted in the brain stem and electrical stimulation was performed. The location of the electrode tips was verified histologically. After stimulation of the lower posterior hypothalamic area, as well as the lower thalamic area, the adrenal 17-OHCS secretion rate increased markedly. When the upper posterior hypothalamic area, or the area preoptica was stimulated, the slight increase in 17-OHCS secretion rate first observed was followed by a marked decrease below the prestimulation level. Stimulation of the capsula interna produced no response in adrenal cortical secretion.