248 



Colchicine 



Kupffer cells 



. , Liver cells 



, .Adrenal cortax 



, Hypophysis,anter. lobe 



O 49 21 23 57 



hours 



Fig. 9.17 — Mitoses in liver and endocrine glands during experimental carbon tetrachlo- 

 ride poisoning, detected by the colchicine-method. (After Cavallero' ) 



the Kuptter cells in relation with the progressive cirrhotic changes 

 on the liver. No mitoses were observed in bile ducts, though the 

 number of these apparently increased.''"^ After 15 inhalations of car- 

 bon tetrachloride, an increased number of reticuloendothelial mitoses 

 could be observed in the spleen. A systematic study of the endocrine 

 glands revealed evidence of mitotic stimulation in the adrenal cortex, 

 the pituitary, and later, the adrenal medullary zone. These divisions 

 do not appear to be related to local damage, and may be an evidence 

 of a pituitary stimulus arising from "stress" (cf. Chapter 7) . 



Some work on the mitotic stinudation in the thyroid of rats in- 

 jected with thiouracil may be mentioned here."*^-^^ -phe stimulus 

 lor cell division is not, however, the chemical itself, but the secretion 

 of the thyrotropic hormone by the pituitary, as mentioned in Sub- 

 section 9.4-1. Colchicine has also helped to study, in experiments 

 of this type, the mitotic changes which take jjlace in the pituitary. i'' 



Results obtained in young rabbits on the influence of thyroidec- 

 tomy and thiouracil on healing of cornea wounds are important to 

 consider under this heading, for they throw light on some difficulties 

 of interpretation.45 Doses of 5 mg/kg of colchicine were injected 4 

 hours before killing the animals. The results are summarized in 



