title: 19F-NMR study of the effect of lead on intracellular free calcium in human platelets.
abstract: Lead has been shown to affect calcium homeostasis. However, there is no prior evidence to indicate an effect of low concentrations of lead in the environment (approximately 1 microM) on the intracellular free Ca2+ concentration in any human tissue. We have investigated the effect of lead on the intracellular free Ca2+ concentration of human blood platelets using 19F-NMR and a fluorinated intracellular Ca2+ indicator. We report a basal intracellular free Ca2+ value of 172 +/- 8 nM. Treatment with 1, 5, 10 and 25 microM Pb2+ resulted in average increases in intracellular free Ca2+ of 39%, 91%, 135% and 172%, respectively. The percent increase in intracellular free Ca2+ was linearly and positively correlated with the log of Pb2+ concentration. Using atomic absorption spectroscopy, a significant increase in total calcium of approx. 10 nmol/mg protein was found in 25 microM Pb2+ treated platelets. This indicates that influx of external Ca2+ contributes to the observed increase in free Ca2+. The results provide an explanation for the previously reported effects of lead on platelet function, and suggest a mechanism for low level lead-induced hypertension.
authors.affiliation: Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, NY.
authors.forename: T L
authors.initials: TL
authors.lastname: Dowd
authors.forename: R K
authors.initials: RK
authors.lastname: Gupta
mesh_terms: D000255:Adenosine Triphosphate / Q000097:blood; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D002118:Calcium / Q000097:blood*; D004533:Egtazic Acid / Q000378:metabolism / Q000031:analogs & derivatives; D006801:Humans; D006973:Hypertension / Q000139:chemically induced; D007424:Intracellular Fluid / Q000187:drug effects; D007854:Lead / Q000097:blood / Q000494:pharmacology* / Q000633:toxicity; D009682:Magnetic Resonance Spectroscopy; D013054:Spectrophotometry, Atomic
chemical_list: D007854:Lead; D004533:Egtazic Acid; C039877:5,5'-difluoro-1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D000255:Adenosine Triphosphate; D002118:Calcium