Peters, E.L., I.R. Schultz and M.C. Newman. 1999. Rb and Cs kinetics and tissue distributions in channel catfish (Ictalurus punctatus). Ecotoxicology 8:287-300.
Abstract We used a two-compartment, clearance volume-based model to examine rubidium and cesium pharmacokinetics in channel catfish (Ictalurus punctatus) after intravascular administration. We compared the apparent volumes of distribution in the central and peripheral compartments and the intercompartmental and whole-body clearances of both metals at 20.0 and 27.5 oC. Biological half-times of Rb were 5 to 7 times shorter than those of Cs in the same individual. Both the intercompartmental and total body clearances of Rb were also 6 to 7 times greater than those of Cs. The apparent volumes of distribution for Rb in the central compartments were twice those of Cs and remained constant with temperature. The apparent volumes of distribution of both elements in peripheral compartments were large compared with their corresponding central compartments, and decreased by a similar extent with increased temperature. Cesium tissue to blood ratios were greatest for white muscle, with more than 85% of the Cs present in this tissue. Tissue binding of Cs apparently decreased with increased temperature conditions.