PHAKMACOLOGY OF HYPOPHYSEAL EXTRACTS 741 



functional part of the hypophysis. Such a limiting conception is not sub- 

 stantiated by the mass of evidence that has accumulated. This has con- 

 clusively demonstrated that the posterior lobe and possibly the intermedi- 

 ary portion also produce secretions of importance to the organism. Never- 

 theless, the function of the anterior lobe in the animal economy is unques- 

 tionably great, and recent studies have shown that its active principle, 

 "tethelin," has a valuable place in therapeutics. 



Effects of Anterior Lobe on Growth. The discovery and isolation of 

 this active principle was the development of many studies of the effects 

 on growth of the administration of extracts or substance of the anterior 

 lobe to various animals. Cerletti (1907), Etienne and Parisot (1908), 

 Sandri (1909), Gushing (1912) and others, all reported a retardation 

 of growth as a result of the ingestion or injection of hypophyseal extracts 

 in young animals. Aldrich(fr) (1912-13) compared the effects on growth 

 of young white rats of extracts of the posterior and anterior lobes and 

 demonstrated that the retardation effect could be attributed to the action of 

 the anterior lobe. Wulzen(a) (1914) found that the growth of young 

 fowls was retarded by the addition to their diet of fresh unmodified anterior 

 lobes of ox pituitaries as determined both by the lesser increase in body 

 weight and length of the long bones. This was supported by similar studies 

 of Pearl (1916), while Maxwell (1916) found that the retardation of 

 growth was not prevented by the administration of thymus substance to 

 the animals ingesting the anterior lobe. Similar results are reported by 

 Lewis and Miller (1913) and White and Titcomb (1914). 



Gn the other hand Schafer(a) (1909) noted that apparently an acceler- 

 ation of growth could be obtained if the substance was fed to animals after 

 they had passed through their early growth period and were about half 

 grown. The variability of the results gave rise to the opinion proposed 

 by Robertson (1916) that the precise nature of the growth influence of 

 the anterior lobe "may be expected to be considerably affected by the stage 

 of development of the animals to which the gland is administered. This 

 view, indeed, finds ample confirmation in the diversity of clinical mani- 

 festations of pituitary insufficiency and the profound extent to which, 

 as Gushing (1912) has exhaustively shown, these manifestations are 

 modified according to whether the pituitary insufficiency or hyperactivity 

 are pre-adolescent or post-adolescent in origin." This belief he confirmed 

 in a series of carefully controlled experiments in which he found that the 

 growth of mice was retarded or accelerated according to whether the an- 

 terior lobe substance was fed early or later in the life of the experimental 

 animals. TJiis principle of a differential effect depending on the age of 

 the animal at time of administration of the effective substance is sup- 

 ported by Wulzen(a) (1916) in her study of fission of planarian worms, 

 and is strengthened by a recent report of Marinus (1919). 



Effects of Anterior Lobe on Gonadal Activity. The administration of 



