206 



HYPOPHYSIS AND GONADOTROPHIC HORMONES 



XIII. The Human Hypophysis 



A. STRUCTURE 



In the human hypophysis (Fig. 3.18j the 

 adenolobe is closely adherent to the neural 

 lobe. The hypophyseal cleft persists in the 

 adult only in its distal portion. The re- 

 mainder of the cleft is obliterated by fusion 

 or is broken up into a number of scattered 

 colloid-filled cysts. 



No pars intermedia is present, conse- 

 quently the pars distalis adheres to the 

 neural lobe. This feature, which is present 

 also in the higher apes, is not found in lower 

 mammals. In the latter there is either a pars 

 intermedia which is adherent to the neural 

 lobe and separates it from the pars anterior, 

 or there is a pars distalis which is not ad- 

 herent to the neural lobe. A full description 

 of the structural features present in the 



Fig. 3.18. Diagram of a .sagittal section through 

 the liuman hyi)oi)hysis. The anterior direction is to 

 the left of the diagram. The adenolobe is occupied 

 by pars distalis tissue (P.d.) containing a mixed 

 cell population throughout and there is no pars in- 

 termedia. Colloid cysts (C.c.) occurring in the re- 

 gion adjacent to the neural lobe are probably rem- 

 nants of the hypophyseal cleft. The adenolobe is 

 adherent to the neural lobe. The neural eminence, 

 the neural stalk, and the prolongation of the neural 

 stalk within the neural lobe are here collectively 

 called the pars eminens (P.e.). The pars nervosa 

 (P.n.) shows an invasion by basophil cells (B) 

 which migrate into the pars nervosa from the pars 

 distalis. The extent of this invasion increases with 

 increasing age and shows great variation in differ- 

 ent individuals. The pars tuberalis is in(lic,il( d In- 

 P.t. 



zone of contact between adenolobe and neu- 

 I'al lobe in the human hypophysis is given 

 Ijy Romeis (1940), who reviews the earlier 

 literature on the subject. 



An invasion of the pars nervosa by baso- 

 phil cells derived from the pars distalis is 

 a unique feature of the human hypophysis. 

 In lower mammals possessing a pars distalis 

 such invasion is not possible because of lack 

 of contact between the two parts. The cells 

 of the pars intermedia in the more usual 

 form of mammalian hypophysis do not 

 show this invasion of the pars nervosa, al- 

 though an irregularity of the plane of con- 

 tact indicates a tendency for mutual in- 

 terpenetration of the two tissues. As stated 

 earlier, the cells invading the pars nervosa 

 of the human hypophysis are intermedin- 

 secreting cells. 



B. SPECIFIC BASOPHIL CELL TYPES IX 

 THE HUMAN HYPOPHYSIS 



The treatise of Romeis (1940) consti- 

 tutes a landmark in the study of the human 

 hypophysis, as indeed for the mammalian 

 liyi)ophysis in general. Romeis' findings in 

 the human hypophysis have, however, de- 

 spite their completeness and their excellent 

 presentation, not had the influence on the 

 development of this subject that might rea- 

 sonably have been expected. The availabil- 

 ity of fresh pituitary tissue from surgical 

 hypophysectomy has changed this situation. 

 U'hen appropriate fixing and staining 

 techniques are used, results equivalent to 

 those described by Romeis can be consist- 

 ently obtained, and even those workers who, 

 through the use of inadequate techniques, 

 have deprived themselves of the oppor- 

 tunity of observing the cell types described 

 by Romeis, must accept the conclusion that 

 such cell types are present and can be re- 

 vealed by appropriate techniques. It is 

 therefore advisable that those who would 

 study the human hypophysis should iden- 

 tify the cells they see with those so clearly 

 delineated by Romeis rather than to em- 

 bark on schemes of classification which 

 Romeis' results show to be inadequate, or 

 to use the terminology of Romeis in applica- 

 tions other than those which he adopted. 



The f3-, 8-, and y-celLs of Romeis are 

 basopiiil cells because their granules give a 



