A method to estimate the DNA content of whole nuclei from measurements made on thin tissue sections

A microdensitometry method that allows estimation of the distribution of the DNA content of nuclei in thin tissue sections is described. The method is based on a theoretical model of Feulgen-stained spherical nuclei, of different sizes, in each of which the DNA is present as a homogeneous solution. In thin sections of nuclei of different sizes, the fraction of DNA per section is inversely proportional to the radius of the nucleus. Histograms of the product of DNA content and radius per nuclear section are independent of nuclear size but depend on total DNA content. The distribution of the total DNA content of nuclei in a section can be estimated from such a histogram. The results of the measurements of a Feulgen-stained rat liver section are described.