Age-related changes in the endocytosis of heat-denatured colloidal albumin by rat Kupffer cells in vitro

In this study, two major functions of rat liver Kupffer cells, viz., endocytosis and catabolism, were determined in relation to age to investigate the cellular basis of the age-related changes in the functional capacity of the RES. Rat liver Kupffer cells were isolated, purified and placed into maintenance culture for 24 hours. The cells were then incubated with 125I-labelled heat-denatured colloidal albumin (CA125I), a clinically used RES test substance. The kinetics of endocytosis and the catabolism of CA125I by Kupffer cells obtained from female BN/BiRij rats of various ages were compared. After incubation of cultured Kupffer cells with various concentrations of CA125I, no differences were observed in the uptake of CA125I by cells from rats of different ages. The capacities of Kupffer cells from young and old rats to degrade and excrete ingested CA125I are compared. Although Kupffer cells from old rats appear to be slightly more effective in the degradation and excretion of CA125I during the first half hour of postincubation, no significant differences between the two age groups were observed. (Auth.)