THE PITUITARY BODY 



of Folley and Kon were made in lactating rats. Lactation 

 was markedly inhibited by the injection of 0.4 mg. of testos- 

 terone propionate per 100 gm. body-weight; on the other 

 hand, three-fourths of this dose of androsterone had no effect. 

 The authors suggest the generalization that substances which 

 cause growth and development of the breasts also inhibit 

 lactation. 



OTHER BIOLOGICAL INTERRELATIONSHIPS 

 OF THE LACTOGENIC HORMONE 



New observations on the distribution of the hormone. — The 

 concentration of lactogenic hormone in the pars glandularis 

 of the sperm whale is less than 1.5 per cent of that in the 

 anterior pituitary of the ox (Geiling, 1935). Leblond and 

 Noble (1937) attempted to determine the amount of lac- 

 togenic hormone in the pituitary of animals of several classes. 

 Their assays were performed in pigeons, into which they 

 made injections intradermally over a crop-gland. They 

 doubted the specificity of some responses because, although 

 undulated thickenings were produced, the cells of the crop- 

 gland contained few or no fat-granules (Scharlach R). The 

 clearest responses were obtained by the injection of the pitui- 

 tary of mammals (mice, rats, rabbits) or of birds (fowls, 

 pigeons). Glands from various fishes were implanted, some- 

 times as many as 100 in a single assay. Attempts also were 

 made to detect and determine the amount of hormone in 

 the pituitary of an amphibian {Rana pipiens) and a reptile 

 {Kinosternon odoratum) . 



The secretion of milk in response to the injection of extract 

 containing the lactogenic hormone. — Grant (1936-37) has in- 

 vestigated the action of lactogenic extract on the regressing 

 mammary glands of the guinea pig. Large doses of the hor- 

 mone caused the transient reappearance of a small amount 

 of mammary secretion which, however, contained little or 

 no lactose (0.04-0. 24 per cent). The volume of secretion was 

 increased tremendously if preliminary treatment with oestra- 



[164] 



