FACTORS INFLUENCING ACTIVITIES OF THE TESTIS 39 



the testis directly. Some of these effects may be mediated through the pituitary 

 gland. As vitamin D is intimately associated with the mineral metabolism of 

 the body, it is not easy to demonstrate its direct importance. 



c. The Hypophysis and Its Relation to Testicular Function 



The word "hypophysis" literally means a process extending out below. 

 The early anatomists regarded the hypophysis cerebri as a process of the 

 brain more or less vestigial in character. It was long regarded as a structure 

 through which waste materials from the brain filtered out through supposed 

 openings into the nasal cavity. These wastes were in the form of mucus or 

 phlegm, hence the name "pituitary," derived from a Latin word meaning 

 "mucus." The word pituitary is often used synonymously with the word 

 hypophysis. 



The hypophysis is made up of the pars anterior or anterior lobe, pars 

 intermedia or intermediate lobe, and a processus infundibuli or posterior 

 lobe. The anterior lobe is a structure of great importance to the reproductive 

 system; its removal (ablation) results in profound atrophic changes through- 

 out the entire reproductive tract. 



The importance of the pituitary gland in controlling reproductive phe- 

 nomena was aroused by the work of Crowe, Gushing, and Homans ('10) 

 and by Aschner ('12) who successfully removed the hypophysis of young 

 dogs. One of the first fruits of this work was a demonstration of the lack of 

 genital development when this organ was removed. Since that time many 

 of the other cohabitants of man — rats, mice, cats, rabbits, etc. — have been 

 hypophysectomized, and in all cases a rapid involution and atrophy of the 

 genital structures results from pituitary removal. The testis undergoes pro- 

 found shrinkage and regression following hypophysectomy, the degree of 

 change varying with the species. In the rooster and monkey, for example, 

 regressive changes are more marked than in the rat. (Consult Smith, '39, for 

 data and references. ) 



A striking demonstration of the influence of the hypophysis upon the 

 genital tract is the result of its removal from a seasonal-breeding species, 

 such as the ferret. Ablation of the pituitary in this species during the non- 

 breeding season causes slight if any change in the testis and accessory repro- 

 ductive organs. However, when it is removed during the breeding season, 

 a marked regression to a condition similar to that present during the non- 

 breeding season occurs (Hill and Parkes, '33). 



The experimental result of hypophysectomy on many animal species thus 

 points directly to this structure as the site of hormonal secretion, particularly 

 to the anterior lobe (Smith, '39). The initial work on the relation of pituitary 

 hormones and the gonad was done upon the female animal. The results of 

 these studies aroused the question whether one or two hormones were re- 



