Steroid Interactions with Serum Proteins Other than Specific Glycoproteins

Abstract

Binding of bile acids to serum proteins was demonstrated early (Rosenthal, 1925) when it was observed that sodium taurocholate at neutral pH displaces acidic dyes (rose bengal, bromsulphalein and others) from their association with blood proteins. Similar competition for anionic binding sites occurs on HSA, as shown by displacement of the anionic dye azorubin by cholic and desoxycholic acid at pH 7.7 (Westphal et al., 1953). No displacement of bromsulphalein from HSA by bile acids was noted at pH 9.1 (Kucerova et al., 1966). Various other observations indicated binding of bile acids to serum proteins (Lecomte du Nouy, 1922, 1928; Rudman and Kendall, 1957 a; Bennhold and Ott, 1961) and to purified HSA (Cohn, 1948). Serum protein binding suppressed the hemolytic activity of desoxycholic acid on red cell membranes (Catanese et al., 1969).