Amounts of RNA

Patrick HJ Falckh p.falckh at rmit.edu.au
Sun May 4 18:37:24 EST 1997


Hi Bruce,

  I have to disagree with Dom Spinella's comment that the amount of RNA 
in a cell is mainly dependent on the protocol for isolating it; yes it 
is important but does not define the actual RNA content in different 
tissues.
  The amount of RNA will depend on the function and activity of the 
cell, which also then takes in the cell type.  For example heart atria 
is a completely different tissue to liver and the amount of RNA is quite 
different.  This can be easily seen when there is induction of 
metabolising enzymes: there is an increase in the amount of protein 
which is related to an increase in the message and an increase in total 
RNA. In the back of the Qiagen Product Guide there is a number of 
appendices that includes a list of cell types and tissues and the 
content of total and messenger RNA per 100mg.  Admittedly this is for 
mouse cells but clearly indicates the varying amount of both total and 
mRNA present. 
  I have extracted total and mRNA from rat out of all the tissues listed 
in the Qiagen list and the values are differnt for that rodent. In 
addition I have extracted RNA from 3 differnt insect species, several 
marine species and their differnt organs and foun quite a difference in 
RNA content even though the method to extract the RNA is essentially the 
same.  Unfortunately, I don't know of a source that lists human tissues.  
One of the numerous companies that makes the extraction kits must have a 
listing somewhere of the differnt amounts in human tissues (one would 
hope they have tessted their kits??!!).

Hope this helps.  
                                                                   
   Patrick HJ Falckh PhD                                 #     #     
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