Methods for screening cellular proliferation using isotope labels

Abstract

The present invention relates to methods for measuring the proliferation and destruction rates of cells by measuring deoxyribonucleic acid (DNA) synthesis. In particular, the methods utilize non-radioactive stable isotope labels to endogenously label DNA synthesized through the de novo nucleotide synthesis pathway in a cell. The amount of label incorporated in the DNA is measured as an indication of cellular proliferation. Such methods do not involve radioactivity or potentially toxic metabolites, and are suitable for use both in vitro and in vivo. Therefore, the invention is useful for measuring cellular proliferation in humans for the diagnosis of a variety of disease conditions in which cellular proliferation is involved.

1 - 49 . (canceled)  
     
     
         50 . A method for analyzing metabolic pathways, comprising: 
 a. administering to a subject a substrate labeled with a stable isotope, wherein the relative isotopic abundance of the isotope in the substrate is known;    b. allowing the labeled substrate to be at least partially metabolized by the subject to form one or more target metabolites; and    c. determining the abundance of the isotope in a plurality of target analytes in a sample from the subject to determine a value for the flux of each target analyte, wherein the plurality of target analytes comprise the substrate and/or one or more of the target metabolites.