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The Effect of Thyroid-feeding and of Thyro -parathyroidectomy 

 upon the Pituitrin Content of the Posterior Lobe of the 

 Pituitary, the Cerebrospinal Fluid, and Blood. 



By P. T. Herring. 



(Communicated by Sir E. Sharpey Schafer, F.E.S. Keceived November 2, 1920.) 

 (From the Physiology Department, University of St. Andrews.) 



The material used for this research was obtained from cats. There were 

 three series of six animals, comprising three males and three females in each 

 group. The animals were healthy adults, of as near a weight and age as 

 possible. One set of six animals was fed with large quantities of fresh ox 

 thyroid for from two to three weeks in addition to their ordinary diet. In 

 the second set thyro-parathyroidectomy was performed on each animal. The 

 cats of the third group were utilised as normal controls. The feeding with 

 thyroid of the first group was begun some time before the operations were 

 done upon the second group. All the animals operated upon showed typical 

 symptoms, and were killed from three to six days after operation. The 

 cerebro-spinal fluid was collected from the fourth ventricle of each cat under 

 ansethesia, the animal then bled, and the blood defibrinated. The pituitary 

 body was dissected out and the posterior lobe separated and dried on a watch- 

 glass rapidly at 37° C. The cerebro-spinal fluid was also evaporated and 

 dried at the same temperature. Similar procedures were adopted in the 

 thyroid-fed animals and in the controls. 



In this way there were collected three materials — dried posterior lobe of 

 pituitary, dried cerebro-spinal fluid, and defibrinated blood — from three 

 groups of animals — normal, thyroid-fed, and thyro-parathyroidectomised cats. 

 The materials were then tested physiologically — by Dale's method upon the 

 uterus of the virgin rat, by Elliott's method upon the blood pressure of a 

 pithed cat, and by their action upon the blood pressure, kidney volume, and 

 secretion of an anaesthetised cat. 



The Posterior Lobe of the Pituitary Body, 



The amount of dried posterior lobe of the pituitary was approximately the 

 same in each group of animals. The material of each group was ground in a 

 mortar, and solutions in Einger's fluid made up of corresponding amounts in 

 each case. A 0*001 per cent, extract of the dried gland was finally adopted 

 as the standard strength for testing. This dilution of posterior lobe acts 

 powerfully upon the rat's uterus. 



