In vivo behavior of fibrinogen fragment D in experimental renal, hepatic and reticuloendothelial dysfunction

Fibrinogen Fg-D, obtained by plasmin-induced cleavage of fibrinogen, was separated and purified by ion exchange chromatography. The in vivo behavior was studied by administering 2 mg of (125)I-labeled Fg-D intravenously into each of 3 normal, 3 partially hepatectomized, 3 reticuloendothelial system (RES) blockaded, 4 nephrectomized and 2 ureter ligated rabbits. The plasma clearance in normal rabbits showed two components: 66.0 +/- 6.0% was cleared with a t(1/2) of 0.9 +/- 0.2 hours and 32.3 +/- 5.3% cleared with a t(1/2) of 3.6 +/- 0.3 hours. In both the partially hepatectomized and RES-blockaded groups, the clearance patterns were similar to those observed in the normal animals. In contrast, in the nephrectomized group, while the t(1/2) of the first component was similar to that in the normal group, the second component had a longer t(1/2) (6.0 +/- 1.0 hours) than the other groups. In the animals with both ureters occluded, the t(1/2)'s were similar to the normal animals. Measurements of urinary radioactivity suggested that complete in vivo catabolism had occurred. In vivo subfragments of Fg-D could not be detected in the plasma. Neither Fg-D nor subfragments were found in the urine. These results indicate that Fg-D is rapidly cleared from the plasma, that in vivo subfragmentation does not occur, and that the kidneys are important in the catabolism of a portion of Fg-D.