[Depletion studies on the essentiality of lead in growing rats]

In model studies with rats it was tested whether symptoms of deficiency could be induced if only lead was removed from an optimal composed diet. For this purpose, one growth experiment and one experiment over generations were conducted. In both experiments depletion diets were fed with a lead concentration of 45 +/- 5 ppb, whereas the control diet was supplemented with 1 ppm lead. In the growth experiment there were no differences in weight and hematological criteria between lead-depleted rats and control rats after 30 days. Similarly in the experiment over generation neither the mother p0 nor the young rats of the f1-generation showed changes in growth rate. However, hematological abnormalities could be measured in these rats of the f1-generation at the day of weaning. In comparison with the control rats the lead-depleted rats showed reduced values of Hct by about 11%, Hb by about 15% and MCV by about 9%. Therefore, these experiments demonstrated first physiological abnormalities as the result of lead-depletion, findings which indicate the essentiality of lead.