NUCLEAR AND CYTOPLASMIC DRUG ACTION I39 



Nuclear and Cytoplasmic Drug Action 



It is not unreasonable to suppose that some substances 

 will exercise their main action upon the cytoplasm of 

 cells and others will have their main action on the nuclei. 

 We can form an initial impression of what the differences 

 may be between these two lines of approach by consider- 

 ing studies upon cells from which the nuclei have been 

 removed. From such experiments we know that cells 

 without nuclei may retain their form, conduct electrical 

 impulses, exhibit the phenomena of amoeboid move- 

 ment, phagoc5^osis and intracellular digestion and even 

 divide. But such cells cannot differentiate and their life 

 appears to be restricted to about 20 days or less. From 

 these phenomena it is tempting to suggest that drugs 

 which have an immediate action exercise their effect pri- 

 marily upon cytoplasmic processes, whereas those with 

 a delayed action have a primary action upon the nucleus. 

 But whilst the first hypothesis may well be correct, more 

 doubt must attach to the second, insofar that there are 

 now reasons for supposing that in addition to the genet- 

 ical activity of the nucleus we must also consider genet- 

 ically active particles in the cytoplasm. 



As an example of the type of phenomenon which has 

 to be considered may be mentioned the case of lewisite. 

 By using transparent chambers for the study of the skin 

 similar to those designed by Clark, it has been shown 

 that large or moderate doses of lewisite cause cell death 



Cell Physiology 9 



