Experimens were performed on 36 cats, showing that stimulation of the central end of the left major splanchnic nerve induced an increase of the plasma cortisol level. The centripetal effect was abolished by lesioning the septal nuclei, just as the same as injection of propranolol into the nuclei; but phentolamine had no such preventive action. All the findings show that it is the noradrenergic beta-receptor system of the septal nuclei that exerts a considerable effect on cortisol secretion.