Abstract
Changes in serous and encephalic serotonin in hypophysectomized or adrenalectomized rats have been observed. Adrenalectomy produces a decrease of serous serotonin and an increase of the serotonin of hemispheres, base, and medulla oblongata; with hypophysectomy, serotonin is also reduced in serum and increased only in the base and medulla oblongata.