PHYSIOLOGY OF ANTERIOR HYPOPHYSIS 



281 



great interest, but the imputation with re- 

 spect to gonadotrophic functions is weak. 

 No glandular parenchyma was found in the 

 nodules. Moreover the rabbit's own pitui- 

 tary, although isolated, remained in situ 

 and, according to the authors, was undam- 

 aged in cytoarchitecture. 



Stalk transection has led to extremely 

 discordant findings with regard to the post- 

 operative structure and function of the pars 

 distalis, particularly in the earlier studies. 

 In Dandy's (1940) often cited case of 

 stalk transection in a young adult woman, 

 the reproductive functions were not im- 

 paired and no symptoms of hypophyseal 

 deficiency appeared, except a severe and 

 permanent diabetes insipidus. Recently 

 Russell (1956j and Eckles, Ehni and Kir- 

 schbaum (1958) observed varying but gen- 

 erally severe necrosis of the anterior lobe 

 following stalk severance in man. The men- 

 strual cycles ceased, and there was a nota- 

 ble regression of the gonads, adrenals, and 

 thyroids; an increase in insulin sensitivity 

 suggested a low output of somatotrophin 

 as well. Quite unexpectedly either si)onta- 

 neous lactation ensued or established milk 

 flow persisted, suggesting output of LTH 

 {vide infra). Russell and Eckles, and Ehni 

 and Kirschbaum agreed that the extent of 

 damage to the anterior lobe is associated 

 with the level of stalk transection, this be- 

 ing most severe wdth low transection. Since 

 in Dandy's patient the stalk was sectioned 

 near the midpoint, it seems likely that the 

 maintenance of the anterior pituitary func- 

 tions he d£Si:iribes is explicable on the basis 

 that a portion of the circulation to the pars 

 distalis escaped damage. The fact that Rus- 

 sell's patients did not exhibit diabetes in- 

 sipidus is in all probability attributable to 

 extreme infarction of the anterior lobe and 

 the poor state of the surviving fragments of 

 this tissue. 



Brooks (1938) found that stalk-tran- 

 sected rabbits, after a period of transitory 

 gonadal regression, had normal appearing 

 pituitaries and ovaries. These animals came 

 into estrus and mated but failed to ovulate. 

 He presumed that the operation had inter- 

 fered with the LH-releasing mechanism. 

 Others, too, in acute experiments have fully 

 substantiated the fact that the postcoital 

 ovulation in rabbits requires the presence 



of an intact stalk (Westman and Jacob- 

 sohn, 1940; Brooks, Beadenkopf and Bojar, 

 1940). In stalk-transected rabbits which 

 have been observed over protracted periods, 

 extensive gonadal atrophy has usually su- 

 pervened (Harris, 1937; Westman and 

 Jacobsohn, 1940; Gaupp and Spatz, 1955). 

 Nine of the 12 rabbits operated upon by 

 Gaupp and Spatz showed extreme atrophy 

 of the gonads and genitalia. The remaining 

 3 reached sexual maturity only after a 

 delay of up to II/2 years. 



Much of the pioneering work on stalk 

 transection or occlusion in relation to ad- 

 enohypophyseal function was done in dogs 

 (Paulesco, 1908; Crowe, Gushing and Ho- 

 mans, 1910; Gushing and Goetsch, 1910) 

 and monkeys (Karplus and Kriedl, 1910; 

 ]\Iorawski, 1911). Gushing and his co-work- 

 ers observed marked anterior lobe degen- 

 eration, and few of their dogs escaped "ca- 

 chexia hypophysioprivia." In their words, 

 "the resultant condition is almost the same 

 as if this portion of the gland had actually 

 been remo^'ed and then reimplanted like a 

 graft, for the circulation is almost entirely 

 cut off." These observations were thor- 

 oughly confirmed by Mahoney and Sheehan 



( 1936) in 20 dogs with stalks occluded. Ex- 

 tensive infarction and central necrosis of 

 the pars distalis with concomitant impair- 

 ment of function was seen in all. Later 

 workers, however, have observed very 

 different sequelae: Keller and Hamilton 



(1937) and Breckenridge and Keller (1948) 

 found no deviations from the normal pat- 

 terns of sexual functions in the majority of 

 their stalk-sectioned dogs. The results in 

 dogs must yet be regarded as inconclusive, 

 inasmuch as regeneration of the portal ves- 

 sels was not adecjuately controlled and the 

 operation is a difficult one, which, at best, 

 involves an indeterminate amount of 

 trauma to the hypophyseal and median em- 

 inence areas. 



Results have been more consistent in 

 monkeys. Karplus and Kriedl (1910) and 

 Morawski (1911) observed no untoward 

 symptoms in stalk-transected monkeys and 

 no obvious alteration in the histologic struc- 

 ture of the pars distalis; and Mahoney and 

 Sheehan (1936) completely occluded the 

 stalk in 20 monkeys with the same results, 

 including no polyuria or polydipsia. At 



