Sexual behavior and elevation of gonadal steroids were induced in both male and female New Zealand white rabbits following injection of synthetic β(1–24) ACTH into the lateral cerebral ventricle. In blood assays collected by cardiac puncture, testosterone, progesterone and corticosterone were all increased above both resting levels and samples were taken after a control intraventricular injection of physiological saline. Parallel increases of plasma LH were also demonstrated. The results were interpreted to indicate that intraventricular ACTH, through LH release, influences sex hormone levels and sexual behavior by acting ‘centrally’, probably within the hypoth