Distribution of Hypophysial Portal Blood in the Anterior Lobe of the Pituitary Gland

Abstract

Complete transection of the pituitary stalk causes extensive bilateral infarction of the pars distalis. In rats, goats and sheep in which the stalk was only partially transected the infarct was smaller and unilateral, being confined to the side on which the lesion had been made in the stalk. This finding shows that groups of portal vessels running down the stalk supply circumscribed areas in the pars distalis, and we believe that this arrangement is part of the system by which the hypothalamus controls the output of specific anterior lobe hormones. It is suggested that the neurovascular link between hypothalamic nuclei and the pars distalis may include many pathways, each with circumscribed areas of origin aswell as termination. Thus, individual groups of anterior lobe cells of similar function could receive specific neurohumors produced by particular groups of hypothalamic nerve cells (Endocrinology75: 120, 1964)