GREGORY PINCUS 



The tissue slice technique merely allows one to demonstrate an accelera- 

 tion or inhibition of a set of metabolic events. But unless the enzyme 

 systems involved are isolated and their activity measured directly, the 

 exact participation of the hormones cannot be accurately worked out. 

 They may be coenzymes at some step in the synthesis of glycogen or 

 they may accelerate the synthesis of an enzyme essential for glycogen 

 production. 



It has indeed been suggested that the protein breakdown that 

 follows administration of adrenal cortex steroid is due to the increase 

 in liver arginase and not to gluconeogcnetic processes. But an increase 

 in kidney arginase occurs in mice receiving steroid substances that 

 promote protein synthesis. Can we explain this apparent discrepancy 

 by saying that liver arginase functions in protein breakdown and 

 kidney arginase in protein synthesis? 



This promotion of protein synthesis by various steroid sub- 

 stances (e. g., testosterone, androstanediol, a-estradiol, and others) is 

 a biochemical phenomenon of great interest and importance. Its 

 elucidation in terms of cellular mechanisms is a preliminary to the 

 explanation of the remarkable series of growth phenomena affected 

 by the steroid hormones. Kenyon's review (5) of the data on man 

 clearly defines the effects of testoids and folliculoids on nitrogen balance. 

 The reader is also referred to Albright's engaging Harvey lecture (1) 

 on Cushing's syndrome for an astute and stimulating discussion of 

 the role of steroid hormones in protein metabolism and osteogenesis. 



It is notable that the principal protein anabolic steroids are 

 testoids, and one is tempted to ascribe the muscularity of the virile 

 male to testis hormone. The proverbial flaccidity of the eunuch 

 tends to strengthen this notion. But when one examines more closely 

 the sex hormone complement of the male, curious anomalies appear. 

 The male animal produces not only testoid but also folliculoid. Cer- 

 tain stallions excrete more estrone into the urine than do pregnant 

 mares. The bull, according to Marker is a remarkable excretor of 

 pregnanediol, the urinary metabolite of progesterone, whereas little 

 or no pregnanediol is excreted by the steer. Conversely, the female 

 animal produces testoid hormone. Ovaries transplanted to the ear 

 of castrated male rats maintain the reproductive organs of the male, 

 but when they are transplanted to warmer sites (e. g., onto the kidney) 

 their testoid activity does not appear. Can we attribute the difference 



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