180 



HYPOPHYSIS AND GONADOTROPHIC HORMONES 



in the normal nonpregnant animal are car- 

 minophil. 



It appears, then, that in a nmiiber of 

 mammals the secretion of somatotrophin 

 and the secretion of prolactin are the func- 

 tions of two distinctive acidophil types, not 

 transformable into one another, and with 

 variable staining reactions in different spe- 

 cies. In most of the species studied thus 

 far, the prolactin-secreting cell is the more 

 carminophil type. In view of the variations 

 in staining affinities which make the dif- 

 ferentiation of two types by staining meth- 

 ods easy in some species and difficult in 

 others, it is possible that in some species 

 two types of acidophil occur whose gran- 

 ules stain alike, and the human hypophysis 

 is presumably one in which the prolactin- 

 secreting cell is the more orangeophil. The 

 variability in the nature of the hormones 

 in different species (the variability of soma- 

 totrophin is particularly well attested) 

 makes this variability in the staining reac- 

 tions of cells serving the same functions in 

 different species credible. 



Some recent observations indicate that 

 more than two acidophil cell types may be 

 present in some species. Herlant (personal 

 communication) has found four distinct 

 acidophil cell types in the pars anterior of 

 the mole {Talpa europanaea), and Ortman 

 and Griesbach (1958) have evidence for 

 four acidophil cell types in the wallaby 

 {Wallabia nifogrisea). 



Purves and Sirett (1959) found prolactin 

 concentrated in the rostral portion and 

 somatotrophin concentrated in the caudal 

 portion of the anterior lobe of the wallaby 

 hypophysis. Somatotrophin, therefore, is se- 

 creted by orangeophil cells in the caudal 

 zone of the pars anterior, and it is probable 

 that the carminophil cells of the rostral 

 zone are the source of the prolactin. 



II. ACIDOPHIL CELLS IN RELATION TO 

 SOMATOTROPHIN SECRETION 



The association of the acidophil cells 

 with the production of growth hormone was 

 first deduced from the observations of acido- 

 phil cell adenomas in the hypophyses of 

 patients showing the symptoms of acro- 

 megaly or gigantism, and, as Gushing and 

 Davidoff stated in 1927, no one today can 

 have anv reasonable doubt that the sul)- 



stance which provokes the overgrowth is a 

 product of the acidophil cells. 



The absence of acidophil cells in the pars 

 anterior of the dwarf mouse (Smith and 

 MacDowell, 1930) is often cited as evidence 

 for the origin of a growth-regulating hor- 

 mone secreted by the acidophil cells. Smith 

 and MacDowell's report indicated that there 

 may be deficiencies in cell types other than 

 the acidophils, but Ortman (1956b) finds 

 that basophils, both /3-cells and 8-cells, are 

 present and appear similar to those present 

 in normal litter mates. It seems, therefore, 

 that there is a specific deficiency in growth 

 hormone secretion associated with a de- 

 ficiency of acidophil cells in these animals. 

 However, the dwarf mice also show evi- 

 dence of deficient thyrotrophic, gonado- 

 trophic, and adrenocorticotrophic secretion 

 and growth may be stimulated in them by 

 thyroxine administration (Nielson, 1952) as 

 well as with growth hormone. Treatment 

 with both hormones is necessarj^ to produce 

 the appearance of full-grown mice. The lack 

 of acidophils in the dwarf mouse hypophysis 

 cannot be due to degranulation of these cells 

 by thyroxine deficiency, because thyroxine 

 administration does not cause regranula- 

 tion. 



Hewer (1943) described a case of human 

 dwarfism in which the hypophysis was 

 markedly deficient in acidophil cells. 



It should be noted that the cessation of 

 growth in the rat after hypophysectomy is 

 due to the loss of thyrotrophin and conse- 

 quently of the thyroid secretion as well as 

 the loss of somatotrophin. This view is 

 necessitated by the observations of Ge- 

 schwind and Li (1952) who showed that 

 either thyroxine or somatotroi)hin produces 

 growth in hypophysectomized rats. Changes 

 in the hypophysis resulting from thyroxine 

 deficiency accompany the arrest of growth 

 which occurs in totally thyroxine-deficient 

 rats. Zeckwer, Davison, Keller and Livin- 

 good (1935) pointed out that the disappear- 

 ance of acidophil cells occurs in the rat hy- 

 pophysis after thyroidectomy and related 

 this to the cessation of growth in such ani- 

 mals, because in partial thyroxine deficiency 

 resulting from incomplete ablation of the 

 thyroid, the acidophil cells were retained 

 and growth continued. The relation of the 

 acidophil cell (Icgvanulation to thvroxine 



