THE PITUITARY BODY 



hormone, must be introduced. An example of the relation- 

 ship between dose and response is the graph of Rowlands re- 

 produced in Figure 21. Rowlands' extract, which contained 

 neither gonadotropic nor thyrotropic hormones, was in- 

 jected subcutaneously once daily for 6 days when the maxi- 

 mum effect was observed. The crop-glands were removed on 

 the seventh day, fixed in Bouin's fluid, and weighed after 

 they had been carried to 70 per cent alcohol. Weights of 



= 12345678 



AMOUNT OF EXTRACT (MGM.) GIVEN DAILY 



Fig. 21. — The relationship between the dose of anterior pituitary extract (con- 

 taining lactogenic hormone) and the growth of the crop-gland of the pigeon. (From 

 Rowlands, Quart. J. Pharm. Pharmacol, lo, 216-21 [1937].) 



crop-glands are expressed as percentages of body-weight. In 

 birds receiving no injections the crop-glands constitute about 

 0.3 per cent of the body-weight. Rowlands recommended 

 that the glands of injected birds should fall within a weight- 

 range represented by 0.8-2.0 per cent of the body-weight. 



Leblond and Allen (1937) stated that the action of lacto- 

 genic hormone could be detected as soon as 10 hours after 

 injection, if 0.5 mg. of colchicine also was administered. 

 After the injection of either the hormone or colchicine, about 

 2 per cent of the cells of the crop-glands were in mitosis; how- 

 ever, if both were injected, "arrested" mitoses were present 



[170] 



