PARS GLANDULARIS AND LACTATION 



diol (0.5 mg. daily for 7 days) followed by progesterone (0.4 

 mg. daily for 4 days) was given. '^ De Fremery (1936) con- 

 cluded that lactogenic extract can initiate the secretion of 

 milk in the goat, irrespective of the season or the phase of the 

 oestrous cycle. Other studies in lactating cows have been 

 made by Waterman, Freud, and Vos-De Jongh (1936) and 

 by Asimov and Krouze (1937). Only two cows were used 

 by Waterman and others whose experiments indicated that 

 lactation is favorably influenced by the hormone. xAsimov 

 and Krouze concluded that milk production is increased ap- 

 proximately 20-40 per cent by the injection of a crude an- 

 terior pituitary extract every 10 days. Five hundred and ten 

 lactating cows which received injections were compared with 

 90 control animals. The effect of the extract was much 

 greater in the first half of the normal period of lactation. 

 Except for a temporary rise of 0.1-0.8 per cent in the con- 

 centration of fat, the milk was found to resemble normal 

 milk. (The pH and the concentration of lactose and chloride 

 were also studied.) 



Among observations in primates are those of Geschickter 

 and Lewis (1936), who studied the action of lactogenic ex- 

 tract in women who had received injections of oestrin for a 

 month previously. The administration of a total dose of 

 600-1,120 bird-units of lactogenic hormone during a week 

 was followed by the elaboration of a secretion which per- 

 sisted only a few days, despite further injections or mechani- 

 cal stimulation. Histological examination of breast tissue in- 

 dicated that true lactation had not appeared. The authors 

 believed that such combined treatment might cause changes 

 resembling cystic disease of the breast. 



The thyroid gland in relation to lactation. '^"^ — Lactation and, 



'^ The injection of 80 units of pregnant-mare serum daily for 3 days prior to the 

 injection of lactogenic extract appeared not to be of value. 



■' Riddle and others (1936-37) pointed out that lactogenic extracts may have a 

 marked calorigenic action in pigeons. This effect, like similar effects of thyroid ex- 

 tract or thyrotropic hormone, can be observed at 30° C. At 20° C. the change 

 may be slight, and at 15° C. it may be in the opposite direction. The calorigenic 



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