title: Chemical and biological monitoring of chronic lead poisoning in the rat. Implications to the assessment of hazard of low-level lead.
abstract: A study on rats of the effects of lead on delta-aminolevulinate dehydratase (ALA-D) activity, and its pH-dependent maximal enzyme activity is reported. Over a 5-week period, the lead burden and ALA-D activity in kidney, liver and brain are documented. Lead concentrations in the organs, expressed as micrograms/g protein are in the sequence kidney greater than liver greater than brain and reach essentially a constant level after 3 days of exposure. This is consistent with the existence of an efficient mechanism removing lead from these organs. Lead affects the ALA-D in all three organs by reducing the activity and shifting the pH of maximum enzyme activity to more acidic values. In common with the lead levels, the ALA-D activity does not deteriorate beyond the levels reached after 3 days of exposure. The existence of a mechanism removing lead from the organs is further supported in a recovery study on blood and kidney, in which both lead level and ALA-D activity return essentially to normal values after 7 days of no exposure to lead.
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D007854:Lead / Q000378:metabolism; D007855:Lead Poisoning / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008297:Male; D000623:Porphobilinogen Synthase / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D007854:Lead; D000623:Porphobilinogen Synthase