HYPOPHYSEAL MORPHOLOGY 



181 



supply was studied by Purves and Gries- 

 bach (1946) who showed that, although 2.5 

 /xg. of DL-thyroxine were required to pre- 

 vent thyroidectomy changes in the baso- 

 phils of the rat hypophysis, the acidophils 

 were protected from degranulation by 0.5 

 ^g. per day and the effect of even smaller 

 quantities in retaining some of the acido- 

 phil cells was observed. The rate of growth 

 observed in these animals was related di- 

 rectly to the content of acidophil granules. 



Degranulation of the acidophil cells oc- 

 curs in rats treated with potent goitrogenic 

 agents. As judged by the acidophil cell re- 

 sponse, thiourea is much less effective than 

 thiouracil in suppressing thyroid secretion 

 because the administration of 0.25 per cent 

 of thiourea in the drinking water does not 

 cause the loss of acidophil cells. 



Using the regranulation of the acidophil 

 cells as a sensitive indicator of small 

 amounts of thyroxine, Purves and Gries- 

 bach (1946) demonstrated that the ad- 

 ministration of iodide in relatively high 

 dosage (1 mg. per day) produced in thy- 

 roidectomized rats an extrathyroidal syn- 

 thesis of material with thyroxine-like activ- 

 ity in amounts which were of physiologic 

 significance. The partial regranulation of 

 the acidophils on high iodide intakes in 

 totally thyroidectomized animals is asso- 

 ciated with continued growth at a subnor- 

 mal rate. They concluded that from injec- 

 tions of 1.3 mg. of potassium iodide per 

 day, approximately 0.12 /xg. of L-thyroxine 

 might be produced. Hum, Goldberg and 

 Chaikoff (1951) showed that injections of 

 iodide (1 mg. per day or more) caused re- 

 granulation of acidophil cells in rats whose 

 thyroid tissue had been destroyed by ad- 

 ministration of radioactive iodine and con- 

 sidered that the effect was due to extrathy- 

 roidal synthesis of thyroxine. 



Marine, Rosen and Spark, (1935) re- 

 ported almost total loss of acidophils from 

 the hypophyses of thyroidectomized rab- 

 bits, but overlooking changes in the baso- 

 phil cells, they related the acidophil cell 

 changes to the production of thyrotrophic 

 hormone. 



In the thyroxine-deficient dog, changes 

 in the acidophil class of cell are apparently 

 limited to the a-cell. Goldberg and Chai- 

 koff (1952b) observed in dogs with com- 



plete thyroid destruction produced by radio- 

 active iodine, a complete degranulation of 

 the a- (orangeophil) cells whereas the e- 

 (carminophil) cells were well preserved and 

 full of granules. The animals were adult and 

 the effect on growth was not observed. The 

 selective degranulation of the a-cells is, 

 however, consistent with the view that these 

 cells are concerned with somatotrophin se- 

 cretion. 



VIII. The Basophil Cell Class 



A. BASOPHIL GRANULES 



In the light of modern knowledge basophil 

 granules are defined as secretory gran- 

 ules containing soluble glycoproteins. The 

 ]\IcjManus (1946) PAS reaction serves as a 

 group reaction for the identification of all 

 granules of the basophil class, as it imparts 

 to them an intense red or magenta color in- 

 dicative of a high content of protein-bound 

 carbohydrate. Glycogen and certain lipoid 

 inclusions are two other intracellular sub- 

 stances which can be colored intensely by 

 the PAS reaction. In paraffin sections pre- 

 treated with diastase these substances will 

 be absent. Insoluble substances of an un- 

 known nature which give a color with the 

 PAS reaction occur in some acidophil cells, 

 and should be sought for in material sub- 

 mitted to extraction before fixation. 



Suitable extraction methods are: (1) 

 Freeze and thaw the tissue on the stage of 

 a freezing microtome three times before fix- 

 ation. Basophil granules will dissolve in the 

 mixture of intracellular and extracellular 

 fluids. (2) Place small pieces of tissue in 

 cold alcohol or acetone for 30 minutes, then 

 in buffer for 1 hour before fixation. This al- 

 lows some control of the pH at least in the 

 peripheral portions of the tissue. (3) Perfuse 

 the animal by way of the aorta with buffer 

 which is saturated with ether at 37°C., or to 

 which desoxycholate has been added as a 

 cytolyzing agent. This method allows the 

 assay of the extracted tissue for content of 

 unextractable hormones. In the other meth- 

 ods the granule contents, although in solu- 

 tion, still remain to a large extent inside 

 the tissue. 



It should be pointed out here that me- 

 chanical damage resulting from the handling 

 of the delicate tissues of the hypophyses of 



