Studies of the integrity of iodinated bovine albumin after circulating in vivo.

The integrity of 125 I BSA circulating in vivo was assessed by immunoprecipitation, antibody binding, and sephadex chromatography. 125 I BSA measurements obtained by precipitation in trichloroacetic acid agreed closely with measurements obtained by antibody binding and immuno - precipitation for up to 12 days after injection or until 99.5% of the 125 I BSA was eliminated. The molecular weight of the circulating 125 I, after dissociation of immune complexes, was identical to non-labelled BSA. 99.5% of the BSA was eliminated from the circulation 10 to 15 days after injection. After this time 45% of the circulating 125 I which precipitated in trichloroacetic acid was not bound to BSA.