Proliferative Capacity of the Hypophysial Portal Vessels

Abstract

THE pathway by which the hypothalamus influences the secretion of the anterior pituitary gland has been the subject of much research. The possibility that the hypophysial portal vessels may form part of this pathway has been discussed¹, and the anatomy of these structures in the rat and other forms has been described. In 1949, Harris² observed that regeneration of the hypophysial portal vessels in the rat may follow section of the pituitary stalk, and later³ that post-operative return of reproductive activity can be correlated with such regeneration. In this work the hypophysial stalk was exposed by the sub-temporal route and either cut with a knife or torn with a hook. In the literature, accounts of stalk section made by a variety of methods show divergent results. Since the conditions for a regeneration of the portal vessels may vary according to the method used for severing the hypothalamo-hypophysial connexions, we have investigated the regenerative capacity of these vessels in different circumstances.