THE PITUITARY BODY 



Meyer, and Simpson mention that their purer preparations 

 produced maximal growth (an increase in weight of 40-60 g. 

 or 16-24 per cent, if one assumes that the adult females 

 weighed 250 g. when the injections were started) in a dose 

 of 5 mg. per day administered seventeen times in a period of 

 20 days. Therefore the total dose used to cause a weight- 

 increase of about 20 per cent in 20 days amounted to 85 mg. 

 All their preparations may have been more potent; only a 

 few were shown to be more potent. What appears to have 

 been the most potent. No. K 18, caused an average weight- 

 increase of 36 g. (about 14 per cent) after the administration 

 of a total dose of 22.8 mg. CoUip, Selye, and Thomson stated 

 that their preparation in a dose of 0.5-1.0 mg. twice daily 

 (total daily dose as total solids, 1-2 mg.) caused a marked 

 growth in hypophysectomized rats. 



The preparation of van Dyke and Wallen-Lawrence un- 

 doubtedly also contained both thyrotropic and gonad-stimu- 

 lating hormones, although the latter were not shown to be 

 present by injections into immature rats but were by means 

 of the ovulation test in rabbits (Hertz, Hellbaum and Hisaw, 

 1932) or in a newt {Triturus viridescens) (Adams, 1934). 

 Some of the preparations of Evans, Meyer, and Simpson 

 caused no change — even when administered in large doses — 

 in the ovaries of immature rats. To this extent only can they 

 be said to have been free from gonad-stimulating hormone. 

 Collip, Selye, and Thomson reported that they had secured 

 preparations apparently free from gonadotropic and thyro- 

 tropic effects. In passing, it may be noted that an extract 

 with growth-promoting properties is not necessarily much re- 

 fined if it has no effects on the thyroid and adrenal cortex of 

 the hypophysectomized rat; for Smith (1930), who produced 

 growth in hypophysectomized rats by injecting a crude ex- 

 tract or a saline suspension of the pars glandularis of the ox, 

 could find no change in the atrophic thyroid and adrenal 

 cortex. 



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