204 



HYPOPHYSIS AND GONADOTROPHIC HORMONES 



basophil classes have also been described 

 in the sow (Cleveland and Wolfe, 1933), 

 rabbit (Wolfe, Phelps and Cleveland, 1934) 

 and guinea pig (Chadwick, 1936). These ob- 

 servations are, however, not easily cor- 

 related with hormonal functions because the 

 differentiation of specific cell types was not 

 achieved. 



F. PSEUDOPREGNANCY AND PREGNANCY 



During pseudopregnancy and pregnancy 

 five distinctive cell types are recognizable 

 in the rat hypophysis as follows. (1) Acido- 

 phil cells, carminophil by Dawson's (1954a) 

 method, in close relation to blood vessels 

 and connective tissue septa and strongly 

 granulated. (2) Acidophil cells, orangeophil 

 by Dawson's (1954a) method, in the interior 

 of the cell cords and large, active, and only 

 lightly granulated. (3) Thyrotrophs which 

 are more prominent and active in this phase 

 than during the estrous cycle. (4) FSH cells 

 which are strongly granulated and at least 

 as prominent as those in the male hypophy- 

 sis and in the immature female. (5) LH cells 

 which are large, round, lightly granulated 

 cells with large and prominent negative im- 

 ages of the Golgi body. 



In animals treated with thyroxine the 

 thyrotrophs are inhibited and no longer 

 seen. Their activity in the untreated animal 

 is probably an indication of an increased 

 demand for thyroxine during this phase of 

 the reproductive cycle. The strong secretory 

 activity which is indicated in the second 

 type of acidophil cell is considered to be 

 related to the secretion of lactogenic hor- 

 mone, whereas the activity of the LH cells 

 is considered to be related to a high level 

 of secretion of LH. The prominence of the 

 FSH cells indicates a retention of FSH. The 

 increased prominence of the FSH cells does 

 not necessarily indicate an increased se- 

 cretion of FSH inasmuch as other condi- 

 tions which interrupt the estrous cycle per- 

 mit the accumulation of glycoprotein in 

 these cells. The increased glycoprotein stor- 

 age correlates with the finding of elevated 

 gonadotrophin levels in the rat hypophysis 

 during pregnancy (Evans and Simpson, 

 1929; Zeiner, 1952). 



The carminoi)hil coll in the rabbit, cat 

 and monkey, shows during the reproductive 



cycle marked fluctuations in activity which 

 can be correlated with the secretion of pro- 

 lactin at times when its luteotrophic or lac- 

 togenic action is manifest (Dawson and 

 Friedgood, 1937, 1938b; Dawson, 1939, 

 1948; Friedgood and Dawson, 1940). 



G. PREGNANCY CHANGES IN THE 

 HUMAN HYPOPHYSIS 



In the human hypophysis the predomi- 

 nant change in pregnancy is the activation 

 of large numbers of cells which are chromo- 

 phobic in the nonpregnant state. These 

 pregnancy cells were first described by 

 Erdheim and Stumme (1909). They lie in 

 the lateral regions of the pars distalis and 

 from the seventh month contain fine acid- 

 ophil granules. These cells have been the 

 source of some confusion and Rasmussen 

 (1933) , finding normal proportions of acido- 

 phils, basophils, and chromophobes in the 

 early months of pregnancy, denied the ex- 

 istence of a specific pregnancy cell although 

 he recognized the enlargement of the chro- 

 mophobes during this condition. Romeis 

 (1940) confirmed the observations reported 

 by Erdheim and Stumme and described the 

 pregnancy cells as large cells with large 

 nuclei. In the second half of pregnancy they 

 show an accumulation of granules which 

 Romeis called 7^-granules. Romeis con- 

 sidered the r;-granules to be a specific type 

 of granule not present in the nonpregnant 

 hypophysis. The granulated pregnancy cell 

 closely resembles the e-cell as seen in the 

 nonpregnant human hypophysis although 

 there are some points of difference. The dis- 

 tribution of the granules is similar and the 

 granules, like those in e-cells, are orangeo- 

 phil. a-Cells, whose granules are carmino- 

 phil, retain their normal appearance in the 

 pregnancy hypophysis. It is probable that 

 pregnancy cells are e-cells in an altered 

 functional state. Floderus (1949) examined 

 the distribution of pregnancy cells in the 

 lunnan hypophysis and found that they are 

 infi'cHinent in the upper posterior part of the 

 pars distalis and are sometimes entirely 

 lacking in this region. They are most abun- 

 dant in the lower lateral parts of the gland. 

 The pregnancy cells are often centrally 

 located in the cell cords with other types, 

 usually ordinary acidophils, located periph- 



