HYPOPHYSIS AND GONADOTROPHIC HORMONES 



the acidophil or basophil cell classes will 

 include all cells in a resting or inactive 

 phase which temporarily do not contain spe- 

 cific granulation, and will also include any 

 specific chromophobe type of cell which 

 does not contain stainable granules at any 

 time. 



The characteristic of the acidophil cells 

 is that they contain specific granules which 

 are of a solid protein nature of high insolu- 

 bility, easily preserved by any method of 

 fixation. These acidophil granules have a 

 strong affinity for acid dyes of all sorts, 

 their degree of acidophilia being somewhat 

 less than that of the hemoglobin of the red 

 blood corpuscles. The cells of the basophil 

 class are characterized by the presence of 

 specific granulation in the form of droplets 

 of glycoprotein which are not highly re- 

 fractile and whose contents are freely solu- 

 ble at physiologic pH. Their retention in the 

 cell depends on the impermeability of the 

 membranes, and they are released or dis- 

 solved when the cytoplasmic integrity is 

 destroyed by cytolytic agents. The glyco- 

 proteins of the basophil cells have affinities 

 for acid dyes which vary among the spe- 

 cific types in any one species and also from 

 species to species. For a rigid division of 

 chromophil cells into the acidophil and baso- 

 phil classes, appeal must be made to an in- 

 vestigation of the chemical nature of the 

 granulation by the PAS reaction. The sub- 

 sequent subdivision of these classes into 

 specific cell types is at present only par- 

 tially achieved by tinctorial methods, and 

 then only in favorable cases. It depends on 

 empiric staining procedures, the results of 

 which are not consistent from species to 

 species. 



B. FAVORABLE SPECIES 



The fii'st feature that would be noticed 

 by anyone who applied standardized stain- 

 ing procedures to pituitaries of a number of 

 manrmalian species would l)e the greatly 

 differing results obtained. These differences 

 depend not only on the relative proj^ortions 

 of the different cell types, but also on the 

 intensity of coloration and quality of the 

 staining reaction. Thus some mammalian 

 species provide pituitaries whose anterior 

 lobes do not at first sight appear promising, 

 because basophil cells occur only in small 



numbers and with weak staining reactions 

 not conducive to their differentiation into 

 specific types. Acidophil cells may seem 

 to be all of one type and all give the same 

 staining reactions, either because only one 

 type is present, or because two types are 

 present but with staining reactions too close 

 to be separated by the standardized arbi- 

 trary procedui'e used. Other species pro- 

 vide pituitaries which, from the first inspec- 

 tion, show themselves favorable for detailed 

 study in that a wider variety of different 

 cell types with strong and distinctive stain- 

 ing reactions is revealed. 



Examples of mammalian i)ituitaries with 

 staining properties favorable to the differ- 

 entiation of the specific types are those of 

 the bat (Herlant, 1956a,), dog (Purves and 

 Griesbach, 1957a), monkey (Dawson, 

 1954bj, and cat (Herlant and Racadot, 

 1957). In these species the presence of five 

 distinctive cell types in the pars distalis can 

 be inferred from the results of the staining 

 procedures. In other species the number of 

 cell types is presumably similar, but the 

 staining reactions of the granules are less 

 favorable for the purjioses of tinctorial dif- 

 ferentiation. 



C. REACTIVITY 



In si)ecies whose pars anterior cells con- 

 tain granules with favorable staining reac- 

 tions, subsequent experimentation will show 

 whether the cell types so revealed will favor 

 the experimenter by marked variations in 

 their appearances in correlation with 

 changes in their secretory activity. In some 

 sj^ecies the variations in appearance, in con- 

 ditions producing widely different levels of 

 secretion of specific hormones, are so small 

 and inconspicuous that much time and care- 

 ful measurement may be necessary to detect 

 the morphologic equivalent of the secretory 

 change. In other species the most striking 

 alterations of cell size, contour, and gran- 

 ule content occur as accompaniments of 

 changes of secretion rate, including the ap- 

 pcarance of new forms and substances which 

 are rarely to be seen in the "normal" pitui- 

 tary. Examples of such changes are the ap- 

 pearance of thyroidectomy cells and castra- 

 tion cells in the rat i)ituitary under 

 conditions producing rapid secretion of thy- 

 rotrophin or gonadotrophins respectively. 



