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Air Quality Criteria for Lead Volume II of II - (NEPIS)(EPA) - US ...

Air Quality Criteria for Lead Volume II of II - (NEPIS)(EPA) - US ...

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AX5-185<br />

Table AX5-10.9 (cont’d). <strong>Lead</strong>, Calcium, and Vitamin D Interactions, and Intestinal Enzymes<br />

Compound and<br />

Concentration Duration Species Blood <strong>Lead</strong> Effects a Authors<br />

Pb, Alkaline phosphatase<br />

and Ca 2+ ATPase<br />

2.0–10.0 mM<br />

Pb, Sucrase<br />

0.5 mM–6.0 mM<br />

Pb, (-glutamyl<br />

transpeptidase1.0–10 mM<br />

Pb, Acetyl choline<br />

esterase 10.00–35.00 mM<br />

Oral Pb in Similac or<br />

apple juice adjusted <strong>for</strong><br />

attainment <strong>of</strong> blood Pb<br />

levels 35–40 µg/dL.<br />

Succimer 30 mg/kg/d<br />

204<br />

Pb 24.5 nM followed<br />

by 206 Pb 352 nM,<br />

Single dose<br />

a CYP—Cytochrome P-450<br />

Incubation time not<br />

specified<br />

Administered from<br />

8th day post partum,<br />

until age 26 wks<br />

Two successive<br />

19 days at age 53 wks<br />

and 65 wks<br />

Administered<br />

immediately be<strong>for</strong>e<br />

chelation<br />

Male Albino rats Pb inhibited the activity <strong>of</strong> several intestinal brush border enzymes such as<br />

Ca 2+ - ATPase, Sucrase, (-glutamyl-transpeptidase and acetyl choline<br />

esterase with the exception <strong>of</strong> alkaline phosphatase. Inhibition <strong>of</strong> Ca 2+ -<br />

ATPase was competitive and that <strong>of</strong> the other enzymes is by noncompetitive<br />

means.<br />

Female infant<br />

Rhesus Monkeys<br />

Pb-exposed:<br />

35–40 µg/dL<br />

Effect <strong>of</strong> oral succimer chelation on the Gastro intestinal absorption and<br />

the whole body retention <strong>of</strong> Pb<br />

Radio isotope Pb tracer technique<br />

Succimer significantly reduced Gastro intestinal absorption <strong>of</strong> Pb and<br />

increased urinary excretion <strong>of</strong> Pb<br />

The initial decrease in whole body Pb by 10% was over come when<br />

majority <strong>of</strong> administered tracer was retained in the body after 5 days <strong>of</strong><br />

treatment.<br />

Gupta et al. (1994)<br />

Cremin et al. (2001)

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