A comparison of bile salt binding to lymph and plasma albumin in the rat.
The binding of bile salts to proteins in rat plasma and rat lymph has been investigated. Under the non-equilibrium conditions of gel chromatography no binding of glycochenodeoxycholate or glycocholate to any of the lymph proteins was observed. In contrast, plasma bound a proportion of both bile salts. When lymph was treated with charcoal, binding of glycochenodeoxycholate to a protein with a molecular weight identical to albumin occurred. Equilibrium binding studies showed that the binding of glycocholate to partially purified plasma albumin exhibited saturation kinetics with a dissociation constant of 2 x 10(-4) M. In contrast, the binding of glycocholate to lymph albumin was non-saturable. Potassium oleate, when added to plasma in a free fatty acid : albumin molar ratio of 3.8 : 1, almost completely inhibited the binding of chenodeoxycholate to plasma albumin. The endogenous free fatty acid : albumin ratios found in systemic plasma and lymph were 0.6 : 1 and 9.2 : 1, respectively. It is suggested that the high free fatty acid concentrations found in lymph inhibit the binding of bile salts to albumin.
D000418:Albumins / Q000378:metabolism*; D000818:Animals; D001647:Bile Acids and Salts / Q000378:metabolism*; D002850:Chromatography, Gel; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D005999:Glycochenodeoxycholic Acid / Q000378:metabolism; D006000:Glycocholic Acid / Q000378:metabolism; D007700:Kinetics; D008196:Lymph / Q000378:metabolism*; D008297:Male; D019301:Oleic Acid; D009829:Oleic Acids / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects; D051381:Rats; D012709:Serum Albumin / Q000378:metabolism*
D000418:Albumins; D001647:Bile Acids and Salts; D005230:Fatty Acids, Nonesterified; D009829:Oleic Acids; D012709:Serum Albumin; D019301:Oleic Acid; D005999:Glycochenodeoxycholic Acid; D006000:Glycocholic Acid