CHAPTER 17 



Mechanism, of Colclucine' Mitosis 



17.1: Introduction 



While many activities of colchicine have been discussed in the 

 previous chapters, it is evident that this alkaloid would be known 

 merely as an effective treatment for gouty patients (Chapter 7) had 

 it not been for its remarkable property of destroying the spindles of 

 mitotic cells. The consequences of this, both in animal and botanical 

 work, have been described. As a polyploidizing agent alone, colchi- 

 cine has become of world-wide importance and has opened new vistas 

 in experimental agiiculture. The scope of the work which has been 

 published since 1934 is so great that all its aspects cannot be covered 

 in this book. More detailed information on some aspects of the 

 colchicine problems may be found in several review papers to which 

 the attention of the reader is directed. i-*- ^^^ -''• •''-• ^•■' '•"• ^'~- ^'^- ^^■ 



77, 81, 97, 102, 18, 111 



Many still unsolved problems have been mentioned in the text, 

 and it would be useless to discuss again their various aspects. How- 

 ever, the main action of colchicine, as evidenced by microscopy and 

 by the production of polyploids, is in changing the properties of the 

 spindle. Other chemical or physical agents are also capable of de- 

 stroying the spindle and preventing mitosis from proceeding. The 

 uniqueness of colchicine appears with greater clarity when it is com- 

 pared with the other "spindle poisons." AV^hile no attempt will be 

 made to cover spindle poisoning, this great field of cellular pharma- 

 cology, it appears evident that the mechanisms of c-mitosis may be 

 better imderstood from the study of other agents altering mitosis like 

 colchicine. Many chemicals closely related to colchicine ha\e been 

 studied, and relations between their chemical structure and their 

 spindle, activity throw light on the possible action of colchicine. 



ly.i-i: Historical. Spindle poisons were kno\vn long before col- 

 chicine, and the fact that none of them was so successful is in itself 



[391] 



