THE EFFECTS OF THYROIDECTOMY UPON THE MAMMALIAN 

 PITUITARY. PRELIMINARY NOTE. By P. T. Herring. (From 

 the Physiology Department, University of Edinburgh.) (With Two 

 Plates.) 



(Received for puhlication 2bfh July 1908.) 



The occurrence in the pituitaiy body of a substance i-esembling the colloid 

 of the thyroid has long been known. The removal of the thyroids is 

 followed in some animals by certain well-marked symptoms ending sooner 

 or later in death; in other animals it has no apparent effect. Rogowitsch 

 (7) went so far as to state that the pituitary acts vicariously for the 

 thyroid, and that in rabbits and other animals which can survive thyroid- 

 ectomy the function of the thyroid is taken over and maintained by in- 

 creased activity of the pituitary. Where the pituitary is relatively small, 

 as in the dog, it fails to do this. Rogowitsch found alterations in the 

 pituitaries of thyroidectomised dogs and rabbits of tlie nature of an increase 

 of certain elements — " Kernhaufen " — in the glandular or anterior portion. 

 He also described the formation of colloid by the chromophil cells of the 

 anterior lobe, and its entry from them directly into the blood-vessels or into 

 small cysts in the " Markschicht." A further change was seen in an in- 

 crease of the number of vacuoles both in the chromophil cells and in the 

 " Kernhaufen." H. Stieda (9) described hypertrophy of the anterior lobe 

 brought about by an increase in the number of " Hauptzellen " with the 

 formation of vacuoles in them. He saw no change in the chromophil cells 

 and no formation of colloid. 



Various other observers, Hofmeister (4), Gley (2), Pisenti and Viola 

 (()), Schonemann (8), have found changes in the pituitary body consequent 

 upon removal or disease of the thyroid. Attention has been confined chiefly 

 to alterations in the epithelial constituents of the pituitary body, little 

 mention having been made of the condition of the nervous portion. Klebs 

 (5) states that he has seen hyaline globules in the blood-vessels of the 

 nervous part of the pituitary of sti'umiprivous dogs, and believes that in 

 this organ is to be sought the " Ausgangspunkt " of the disturbance. 

 Boyce and Beadles (1) found, in cases of myxtTedema, enlargement of the 

 pituitary body with increase of colloid in the posterior part of the anterior 

 lobe. Large cysts containing colloid were present in this situation which 

 they termed the medullary layer. The posterior lobe was atrophied but 



