Serum Copper and its Relationship to Serum Iron in Patients with Neoplastic Disease

The importance of serum copper in the transport of copper throughout the body was established by Sachs, Levine, Schmit, and Hughes (1941) when they observed that the oral administration of varying amounts of copper sulphate was followed by a definite rise in the copper content of the serum.Later Yoshikawa, Hahn, and Bale (1942) obtained a similar result by feeding radio-active copper salts to normal and anaemic dogs.After its ingestion the tagged metal rapidly appeared in the serum, reaching its peak concentration within two to five hours.These observations indicate that the role of serum copper in copper metabolism is analogous to that of serum iron in iron metabolism, and, by permitting valid conclusions to be drawn from estimations of serum copper levels, have facilitated the study of copper meta- bolism in man.The purpose of this paper is to present the values of serum copper obtained in normal subjects and in patients with neoplastic disease unaccompanied by haemor- rhage, and to compare the iron and copper concentrations in the serum of these patients.Methods Serum copper was determined by a minor modification of the technique described by Cartwright, Jones, and Wintrobe (1945).This method consists of the triple extraction of the trichloracetic acid precipitate of serum and the development of the coloured copper-dithiocarbamate complex, the resultant colour being measured directly in the aqueous extract.Difficulty was encountered in obtaining optically clear aqueous extracts for photometry, however, and extraction of the coloured complex with amyl alcohol, as originally suggested by McFarlane (1932), was there- fore employed.The procedure finally adopted was as follows.The aqueous phase, obtained by following the procedure of Cartwright et al., was made up to a volume of 20 ml. with distilled water in a graduated test-tube, 10 ml. of amyl alcohol added, and the test tube shaken vigorously for two minutes.The amyl alcohol phase was then separated by centrifugalization and transferred by a Pasteur pipette to a thoroughly dried 1 cm.optical cell.Colour was measured in a Spekker absorptiometer using the Ilford spectrum filter, No. 601.Clear extracts of the coloured copper complex were consistently obtained when this procedure was followed.Serum iron was estimated by the method of Fitzpatrick and Howells (1949), by whom it has already been described in detail.The Haldane method was used for haemoglobin determination.