Uptake and degradation of radioactively labelled albumin microspheres as markers for Kupffer cell phagocytosis.

Rats were injected with liposomes containing iodixanol (CTP10 Injection; 100 mg iodine per kg body weight) followed by a second injection of 125I-tyramine-cellobiose-albumin microspheres. The amounts of phagocytosed and degraded labelled albumin in liver were measured. A reduced uptake and degradation of albumin microspheres was observed when the labelled microspheres were injected 2 h or 24 h after the liposomes compared with that obtained in control animals receiving saline. No effect on the uptake and degradation of labelled microspheres was observed when the time lag between the injection of liposomes and labelled microspheres was 1 week. The data show that the uptake and degradation of 125I-tyramine-cellobiose-albumin microspheres can be used as indicators of Kupffer cell phagocytotic function following drug uptake by these cells.