PARS GLANDULARIS AND LACTATION 



The pituitary gland of broody hens produced much more 

 hypertrophy of the crop-gland than that of laying hens or of 

 cocks. Other comparisons between the pituitaries of hens of 

 broody or non-broody genetic constitution indicated again 

 that broodiness is associated with the larger amount of lacto- 

 genic hormone in the pituitary. 



Leblond and Nelson (1937) concluded that the maternal 

 instinct in lactating mice and rats does not depend upon the 

 secretion of lactogenic hormone because the instinct persists 

 after hypophysectomy. 



De Fremery (1936) was able to terminate pregnancy, either 

 as fetal death or abortion, by the injection of lactogenic ex- 

 tract into pregnant goats, guinea pigs, rabbits, or rats. He 

 stated that the effect was not due to gonadotropic or thyro- 

 tropic hormone. 



According to Salle and Schechmeister (1936), embryonic 

 crop-gland cultured in vitro is not affected by lactogenic ex- 

 tract. The growth of the Simpson mammary carcinoma in 

 mice is not altered after the injection of 60 bird-units of lac- 

 togenic hormone (Bischoff and Maxwell, 1936). 



The metabolism of the lactogenic hormone. — Wiegand (1937) 

 found that little change in the amount of lactogenic hormone 

 is found in the pituitary body of the rat during pregnancy. 

 Immediately after parturition the amount present is doubled 

 or trebled; however, the quantity of the stored hormone falls 

 as it is liberated into the blood stream and lactation appears. 

 Perhaps a similar change occurs in women. At any rate, 

 several authors have demonstrated lactogenic hormone in the 

 urine of lactating women. Like Wiegand, these authors relied 

 on the hypertrophy of the pigeon's crop-gland to detect the 

 hormone.'^ Lactation in new-born children — the secretion of 

 "witches' milk" — is attributed by Lyons (1937) to the action 



'* Lyons and Page (1935), Hoffmann (1936), and Tesauro (1936). Lyons and 

 Page estimated that the daily excretion of hormone in the urine of women 4-13 

 days after parturition was at least equivalent to what can be extracted from one 

 pars glandularis of the ox. Liard's experiments (1937) appear not to be adequately 

 controlled. 



[167] 



