Kinetics of orally administered ⁹⁰Y-DOTA-conjugated bovine lactoferrin in the mouse gastrointestinal tract: a preliminary study

Abstract

 Objective: The ingestion of bovine lactoferrin (LF) has antimicrobial and immunomodulatory effects in clinical trials. To understand the mechanisms of action underlying these biological functions of ingested LF, the kinetics of radiolabeled LF in the gastrointestinal tract were investigated. Methods: 1, 4, 7, 10-tetraazacyclododecane-N, N′, N′′, N′′′-tetraacetic acid (DOTA) was reacted with LF to form an amide bond. The amount of DOTA bound to LF was investigated by mass spectrometry. Radioactive yttrium (⁹⁰Y) was chelated to DOTA or DOTA-conjugated LF. ⁹⁰Y-DOTA or ⁹⁰Y-DOTA-conjugated LF was orally administered to mice, and the distribution of the radioactivity was evaluated by whole-body autoradiography. Results: The ratio of DOTA bound to LF was 1：1. The radioactivity was detected mainly in the stomach and partly in the small intestine at 10 min, and slightly in the stomach and mostly in the small intestine at 60 min after the administration of ⁹⁰Y-DOTA-conjugated LF, whereas the radioactivity was detected slightly in the stomach and small intestine, and mostly in the cecum at 60 min after the administration of ⁹⁰Y-DOTA. Conclusion: The radioactivity was mainly detected in the small intestine in the mice administered ⁹⁰Y-DOTA-conjugated LF. Ingested LF may act on the small intestine and perform a variety of biological functions.