HYPOPHYSEAL MORPHOLOGY 



197 



adrenalectomy, there remain always a few 

 active normal-looking cells. Colombo (1948, 

 1949) reported in rats, after bilateral or 

 unilateral adrenalectomy, a change in baso- 

 phil cells similar to that occurring after 

 castration and not accompanied by any 

 change in acidophil cells. 



Griesbach (personal communication) ob- 

 served that the LH cells were enlarged after 

 adrenalectomy in the rat. There were also 

 changes in thyrotrophs similar to those 

 produced by exposure to cold. The changes 

 in the thyrotrophs were prevented by thy- 

 roxine administration. Knigge (1957) found 

 the thyrotrophs diminished in numbers after 

 adrenalectomy. The gonadotrophs (8-cells 

 of Halmi) were unchanged in numbers but 

 were hypertrophied, and some of them were 

 hyalinized 8 weeks after adrenalectomy. 

 Knigge suggested that the 8-cells were the 

 source of corticotrophin. 



Rokhlina ( 1940) tested the effects of com- 

 bining adrenalectomy with castration in 

 rabbits and rats. In some rats thus treated 

 no castration changes appeared in the baso- 

 phil cells, whereas in others the transforma- 

 tion was delayed. Adrenalectomy performed 

 on the 30th day after castration had some ef- 

 fect on the further develojimcnt of castration 

 changes. 



Brokaw, Briseno-Castrcjon and Finerty 

 (1950) performed unilateral adrenalectomy 

 on rats. By this means a relative adrenal 

 insufficiency should be produced without 

 the extensive metabolic disturbances accom- 

 panying complete adrenal deficiency. They 

 observed a temporary increase in the pitu- 

 itary acidophil cell percentage; the normal 

 pituitary cytology was regained in approxi- 

 mately 50 days. 



Herrick and Finerty (1940) found in 

 adrenalectomized fowls an alteration in 

 basophils in the pars distalis, which they 

 correlated with the regression of the testes. 

 The basophils showed progressive vesicula- 

 tion, the vesicles being filled with hyaline 

 material. They considered these basophils 

 to be in a degenerating state. IMikami 

 (1957) observed a degeneration of both 

 thyrotrophs and gonadotrophs in the fowl 

 after adrenalectomy. In addition there was 

 a degranulation and remarkable enlarge- 

 ment of a third basophil type in the rostral 

 zone of the pars distalis. These cells, desig- 



nated by Mikami "V cells," were considered 

 to secrete corticotrophin. 



In the dog, Mikami (1956) found that the 

 ^cells of Goldberg and Chaikoff (1952a) 

 increased in number and enlarged in size 

 after adrenalectomy. These were the only 

 cells showing signs of increased activity 

 after adrenalectomy. The ^-cells of Gold- 

 berg and Chaikoff are the cells termed 

 "pale" cells by Purves and Griesbach 

 (1957a) and are basophil cells with a low 

 content of granules. 



C. HYPOPHYSEAL RESPONSES TO STRESS 



An increased secretion of corticotrophin 

 is produced in response to many different 

 kinds of stress. Inasmuch as adaptation to 

 various kinds of stress wall involve changes 

 in a number of hormones, the hypophyseal 

 responses to stress will be less suitable for 

 the study of corticotrophin production than 

 the specific disturbances produced by adre- 

 nal insufficiency. Thus, the response to cold 

 exposure involves increased secretion of 

 thyrotrophin as well as corticotrophin, and 

 the increased activity in the basophil cells 

 of the rat exposed to cold have been related 

 thyrotro{)hin production rather than corti- 

 cotrophin (Brolin, 1945; Allara, 1953; 

 ]McXary, 1957). In rats exposed to cold, 

 Griesbach, Hornabrook and Purves (1956) 

 observed partial degranulation of thyro- 

 trophs and early hyalinization giving rise 

 to cells with a resemblance to Crooke's cells. 

 This appearance is related to alteration in 

 thyrotrophin secretion and can be pre- 

 vented by thyroxine injections, but not by 

 replacement with cortisone. 



An increased granule content in basophil 

 cells in the rat during inanition has been re- 

 lated to an increased storage of gonadotro- 

 phin (Pearse and Rinaldini, 1950). The in- 

 crease in stainable basophils observed in 

 the hypophyses of animals subjected to 

 various forms of stress may, therefore, be 

 related to changes in the content of the gly- 

 coprotein hormones which are the specific 

 secretory products of these cells. Herlant 

 (1936a, b) observed that the increase in 

 stainable basophils in the rat hypophysis 

 after ligation of the ureters or after the in- 

 jection of hydrochloric acid, was accom- 

 panied by an increase in the gonadotrophic 

 potency of the pituitary tissue. 



