How does the physiologically active substance which is constantly found in the posterior lobe of the hypophysis find its way into the blood stream? In 1908, Herring1 reported the presence of colloid and hyaline bodies in cats in the pars intermedia and the pars nervosa which he believed passed through the infundibular stalk and into the third ventricle. These bodies appeared to break up into granules before entering the third ventricle. Herring considered this colloid and hyaline material to be the secretion of the gland, produced by the pars intermedia and passed into the pars nervosa by some unknown means.
The question of whether the physiologically active substance, pituitary extract, is the product of the pars intermedia or pars nervosa is beyond the scope of this paper and will not, therefore, be discussed. Assuming that pituitary extract is an internal secretion, is it discharged into the cerebrospinal fluid before
SHAPIRO S. THE PRESENCE OF AN OXYTOCIC SUBSTANCE (POSTERIOR HYPOPHYSIS EXTRACT) IN CEREBROSPINAL FLUID. Arch NeurPsych. 1926;15(3):331-340. doi:10.1001/archneurpsyc.1926.02200210052005