Franano FN, Edwards WB, Welch MJ, Duncan JR. Metabolism of receptor targeted 111In-DTPA-glycoproteins: identification of 111In-DTPA-epsilon-lysine as the primary metabolic and excretory product.
Nucl Med Biol 1994;
21:1023-34. [PMID:
9234360 DOI:
10.1016/0969-8051(94)90174-0]
[Citation(s) in RCA: 44] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The hepatic and renal retention of indium-111 (111In) from 111In-labeled polypeptides has been the subject of many investigations. Because the lysosome is a common intracellular destination for the degradation of polypeptides, we studied the lysosomal metabolism of 111In-DTPA-labeled glycoproteins targeted to cell surface receptors in vitro and in vivo. We found that 111In-DTPA-glycoproteins were degraded to 111In-DTPA-epsilon-lysine, which was slowly released from cells and recovered intact in urine and feces. These results suggest a mechanism for 111In retention at target and non-target sites.
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