Disposition of Lead (Pb) in Saliva and Blood of Sprague-Dawley Rats Following a Single or Repeated Oral Exposure to Pb-Acetate

Journal Article · Mon May 01 04:00:00 EDT 2006 · Toxicology

DOI:https://doi.org/10.1016/j.tox.2006.01.030· OSTI ID:886716

Timchalk, Chuck; Lin, Yuehe; Weitz, Karl K; Wu, Hong; Gies, Richard A; Moore, Dean A; Yantasee, Wassana

Biological monitoring for lead (Pb) is usually based upon a determination of blood Pb concentration; however, saliva has been suggested as a non-invasive biological matrix for assessing exposure. To further evaluate the potential utility of saliva for biomonitoring, the disposition of Pb was evaluated in whole blood (WB), red blood cells (RBC), plasma, parotid gland, bone, and saliva following either a single oral dose of 100 mg Pb-acetate/kg body weight in rats or {approx}1-week after 5 sequential daily oral gavage doses of 1, 10, or 100 mg Pb-acetate/kg/day. Saliva volume, pH, total saliva protein, and ?-amylase activity were also determined. At specified times post-dosing groups of animals were anethetized and administered pilocarpine to induce salivation. Saliva was collected, the animals were humanely sacrificed, and tissue samples were likewise collected, weighed, and processed for Pb analysis. Following a single dose exposure to PB-acetate, Pb was detectable in all samples by 30 min post-dosing. For both the single and repeated dose treatments the concentration of Pb was highest in WB and RBC relative to plasma and saliva. However, the Pb rapidly redistributed (within 5-days post-treatment) from the blood into the bone compartment based on the substantial decrease in WB and RBC Pb concentration, and the concurrent increase in bone Pb following repeated exposure at all dose levels. Although there is clear variability in the observed Pb concentrations in plasma and saliva, there was a reasonable correlation (r2=0.922) between the average Pb concentrations in these biological matrices which was consistent with previous observations. The single oral dose of Pb-acetate resulted in a decrease in salivary pH which recovered by 24 hr post-dosing and a decrease in ?-amylase enzyme activity which did recover within 5-days of ceasing exposure. It is currently unclear what impact these slight functional changes may or may not have on Pb salivary clearance rates. These results demonstrate a feasibility to rapidly detect Pb in saliva and suggest that saliva may correlate best with plasma Pb concentration.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 886716
• Report Number(s): PNWD-SA-7231
• Journal Information: Toxicology, Journal Name: Toxicology Journal Issue: 1-2 Vol. 222; ISSN 0300-483X; ISSN TXCYAC
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
AMYLASE
ANIMALS
BLOOD
BLOOD CELLS
CLEARANCE
COMPARTMENTS
ENZYME ACTIVITY
FUNCTIONALS
Lead
Saliva
MATRICES
MONITORING
Oral Exposure
PILOCARPINE
PLASMA
Pharmacokinetics
Rats
SALIVA