200 



HYPOPHYSIS AND GONADOTROPHIC HORMONES 



ing granules with a content of soluble glyco- 

 proteins. In the rat the granules are much 

 more strongly stained by aldehyde-fuchsin 

 than by PAS, and show an additional differ- 

 ence of behavior from the basophil granules 

 of pars anterior cells in that their staining by 

 aldehyde-fuchsin is not enhanced by prior 

 oxidation with acid permanganate (Halmi 

 and Davies, 1953). 



The granules of intermedia cells stain a 

 blue or purple color by trichrome staining 

 methods (Romeis, 1940). In the cat, in 

 which the staining reactions of intermedia 

 cells are strong due to a high content of 

 granulation the appearance of intermedia 

 cells in stained sections is similar to that of 

 typical pars anterior basophils. 



The relation between the specific granules 

 and the hormone secretion of the pars inter- 

 media cells is still obscure. The hormone can 

 be obtained as a peptide, but it may be that 

 a combination of this peptide with the gly- 

 coprotein is the form in which the hormone 

 is first produced and stored. Ortman (1954, 

 1956c) found in the frog that the glycopro- 

 tein granules of the pars intermedia cells 

 were depleted during dark adaptation, but 

 did not find any accompanying reduction in 

 hormone content. 



Not all hypophyses have a pars inter- 

 media, although so far as is known all con- 

 tain intermedin. In birds as a class, and in 

 certain mammals, porpoise, whale, arma- 

 dillo, manatee, elephant, pangolin, beaver, 

 and man, the pars intermedia is absent. The 

 problem of the cellular origin of the inter- 

 medin in hypophyses of this type is of great 

 interest because of indications that one of 

 the basophil cell types of the human pars 

 distalis is the intermedin secretor of this 

 species. In the porpoise and whale inter- 

 medin is present in the tissue of the adeno- 

 lobe (Oldham, Last and Gelling, 1940), and 

 although the specific cells which produce the 

 hormone have not been identified, it must 

 be assumed that they are present, scattered 

 throughout the pars distalis. A similar dis- 

 tribution of intermedin was shown in the 

 beaver by Kelsey, Sorenson, Hagen and 

 Clausen (1957). In birds the intermedin is 

 found only in the rostral portion of the 

 adcnolol)c (De Lawder, Tarr and Gelling, 

 1934; Mialhe-Voloss and Benoit, 1954). In 



hen and duck hypophyses I have found 

 aldehyde-fuchsin positive basophil cells in 

 the rostral zone of the pars distalis, but the 

 correlation with the distribution of the hor- 

 mone is obscured by the presence of other 

 aldehyde-fuchsin positive cells in the caudal 

 zone. In the white-crowned sparrow [Zono- 

 trichia leucophrys gambellii) aldehyde- 

 fuchsin positive basophils are found only 

 in the rostral zone. Traces of thyrotrophin 

 are present; the concentration is the same 

 in both zones. It may be that the aldehyde- 

 fuchsin positive cells of the rostral zone 

 are the intermedin secretors. 



Much more definite information about 

 the human hypophysis is available from the 

 studies of ]\Iorris, Russell, Lanclgrebe and 

 Mitchell (1956). These investigators cor- 

 related the hormone content of small por- 

 tions of tissue from the anterior lobe, neural 

 lobe, and areas of basophil cell invasion in 

 the neural lobe, with the numbers of baso- 

 phil cells present. The selection of appro- 

 priate parts was made by the use of an 

 elegant method in which the presence of 

 basophil cells could be ascertained by ex- 

 amining a pinhead-sized fragment. The re- 

 sults showed that intermedin was present in 

 high concentration in the anterior lobe, 

 whereas it was almost entirely absent from 

 neural lobe tissue. Neural lobe tissue show- 

 ing invasion by basophil cells was, however, 

 equivalent in hormone content to samples 

 from the anterior lobe. The invasion of the 

 neural lobe by basophilic cells, which is a 

 phenomenon peculiar to the human hy- 

 pophysis, has permitted here the demonstra- 

 tion that cells containing glycoprotein se- 

 crete intermedin. For the identification of 

 the specific type of cell responsible for inter- 

 medin secretion in the human pituitary, we 

 can take advantage of the fact that although 

 a number of basophil cell types can be seen 

 in the pars distalis, the cells that invade the 

 n(>ural lobe are of a single tyj^e. Thej^ are 

 composed entirely of a variety of Romeis' 

 (1940) /?-cells which stain with aldehyde- 

 fuchsin and take a red oi' pui|)l(' shade 

 from the trichrome counter stain. These 

 cells will be designated as "purple ^-cells." 

 Morris, Russell, Landgrebe, and Mitchell 

 (1956) referred to these invading cells as 

 8-cells; they are, however, quite distinctly 



