[Elimination of lead from rats under biological stress, and application of Na2Ca-EDTA (author's transl)]

It is currently thought that lead is released from organic depots in response to internal or external stress to the organism. Using young Wistar rats, we were unable to confirm this view. Chronic lead levels, persisting over a period of 20 days, were achieved by the intraperitoneal injection of labelled (210Pb) lead acetate into rats (5 mg/kg body weight). The animals were divided into four groups. One group was maintained normally as a control, while two others were subjected to stress, i.e. starvation and injection of an autolysate of bacteria, respectively. All three of these groups showed identical behaviour with respect to total body radioactivity, femur radioactivity (representing the chief skeletal depot), and excretion of radioactivity. The fourth group received Na2Ca-EDTA (sodium salt of the calcium chelate of ethylenediaminetetraacetic acid). The decrease of total body radioactivity and femur radioactivity, and the relative excretion of 210Pb had almost levelled out by about 14 days, and was related mainly to the elimination of lead from the bones (in parenchymatous organs, the cell membrane forms a barrier to the therapeutic removal of intracellular lead). This illustrates the effectiveness of early treatment in lead poisoning, and the ineffectiveness of continuous therapy.