A colorimetric method for the determination of deoxyribonucleic acid in adipose tissue

A method is described for measuring the deoxyribonucleic acid (DNA) content of small samples of adipose tissue or free fat cells. Lipids and acid-soluble nucleotides are first removed by extraction with a cold diethyl ether-ethanol mixture containing 10 per cent. m/V of trichloroacetic acid. DNA is then measured by hydrolysing the nucleoprotein residue in a 5 per cent. solution of trichloroacetic acid at 90 °C for 20 min, followed by treatment with p-nitro-phenylhydrazine and measurement of the hydrazone at 560 nm.Several aspects of the method have been critically examined in order to determine the optimum conditions. The method is satisfactorily reproducible.