AZORUBIN-BINDING CAPACITY AND PROTEIN COMPOSITION OF SERUM OF RATS SUBJECTED TO TOURNIQUET SHOCK AND TO TREATMENT WITH CARBON TETRACHLORIDE

Abstract

The cause of a decreased azorubin-binding ca-pacity (ABC) of serum albumin, previously ob-served in humans under certain pathological con-ditions (1), is not known. The present paper is part of an experimental study into the mechanism of a lowering of the ABC (2). It describes the production of decreased ABC values of serum al-bumin of rats by subjecting them to tourniquet shock or to treatment with carbon tetrachloride. In addition, the serum protein composition of these experimental rats, was analyzed, since changes in the protein metabolism have been ob-served in traumatic shock (3, 3a). EXPERIMENTAL Chemical procedures. For the determination of the pro-tein and non-protein nitrogen, the micro-Kjeldahl method of Hiller, Plazin, and van Slyke (4) was used, with some modifications which are described elsewhere (5). The non-protein nitrogen was separated from the serum pro-teins by precipitation with uranyl acetate according to the procedure of Neubauer (6). One ml. of serum was diluted with 3 ml. of water, and 1 ml. of 1.5 per cent uranyl acetate was added, with stirring, to the solution. The protein was filtered off after 60 minutes, using a Whatman No. 50 filter. Since preliminary experiments indicated that a chemi-cal determination of serum albumin with a 26.8 per cent sodium sulfate solution (7, 8) gave low values (for de-tails see [5]), all albumin determinations were done by electrophoretic analysis. Electrophoretic analysis. The veronal-acetate-sodium chloride buffer of Michaelis, pH 8.6, /z = 0.1, was em-ployed (9). Practically identical patterns were obtained in veronal buffer as used by Moore, Levin, and Leathem for rat sera (10). All pH measurements were done at room temperature with a glass electrode. The electro-phoretic analyses were carried out in the compact Tiselius apparatus 1 (11), employing the Longsworth scanning mechanism and the 2 ml. cell in an open system. Some sera were also analysed in a standard size Tiselius electro-phoresis apparatus 2 using the long analytical cell (12);