THE PITUITARY BODY 



steps: adsorption on norit from a weakly alkaline solution, 

 elution of the hormone by phenol, and subsequent precipita- 

 tion by a solution of one part of alcohol in two parts of ether. 

 The authors also concluded that the hormone could dialyze 

 through collodion membranes and that the nitrogen content 

 of the material in the sac was higher than that of the dialyzed 

 material. The dialysis was performed at a very high pH 

 (o.oi NNaOH). 



Summary. — The clear-cut identification of a growth-pro- 

 moting hormone in the anterior pituitary is perhaps the prob- 

 lem of greatest immediate importance to those interested in 

 this aspect of the physiology of the pituitary body. On the 

 other hand, if such a hormone is not secreted by the gland, 

 new interpretations of much satisfactory data will have to 

 be made. It is still possible, however, provisionally to use the 

 term "growth-promoting hormone." 



Few of the recent observations require reference in this 

 summary. Experimentally, changes in bones and joints, 

 some resembling those of acromegaly, have been more exten- 

 sively studied. Additional data on general biochemical 

 changes due to hypophysectomy have been secured. As far 

 as other glands of internal secretion are concerned, there is 

 additional evidence, at least in the rat, that the oestrogenic 

 secretion of the ovary may act as a brake on general growth. 

 Endocrine glands such as the thyroid, adrenals, thymus, and 

 epiphysis may affect growth — sometimes positively, some- 

 times negatively. How such effects are related to excessive or 

 reduced secretion of the growth-promoting hormone in no 

 case has been convincingly demonstrated. The growth of 

 malignant neoplasms may be slightly favored by anterior 

 pituitary secretion; this effect, however, appears not to be im- 

 portant. Recently little attention has been paid to the purifi- 

 cation of the growth-promoting hormone. This may prove 

 to be an impossible task made even less attractive by the dif- 

 ficulties of accurate assay. 



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