Associative mechanism lead poisoning

Despite the prevalence of lead poisoning and the seriousness of the health problems associated with lead poisoning, many fundamental questions about the mechanism of lead poisoning still remain unanswered (29). These include... 

The tris(mercaptoimidazolyl) ligand TmAr has been employed to emulate the coordination environment of 5-aminolevulinate dehydratase (ALAD). Several ZnX(TmAr) have been described145-147 that also have helped in the knowledge of the mechanism of action of ALAD. To study the lead poisoning that is associated with lead interaction with ALAD, PbX(TmAr) complexes have been also reported.148... 

Thus, it is clear that the impairment of heme synthesis by lead exposure occurs at relatively low BLLs and that increased concentrations of ALA and protoporphyrin are associated with lead exposure. However, it is not widely recognized that the inhibition of heme synthesis cannot fully explain the anemia of lead poisoning. The elegant work of Piomelli et al. (1975) has demonstrated that even in patients with BBLs over 90 pg/dL, erythrocytes contain roughly 300 molecules of heme for every molecule of free protoporphyrin. Thus, other molecular mechanisms must play more important roles in the etiology of the anemia. 

Lead is often associated with an iron deficiency. When lead poisoning patients are iron deficient, they absorb more lead. Also, there may be similar mechanisms by which iron deficiency and lead affect growing cells, including brain cells. ... 

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