Estimating the oral bioavailability of methylmercury to channel catfish (Ictalurus punctatus)

Journal Article · Wed Aug 12 04:00:00 EDT 1998 · Environmental Toxicology and Chemistry

DOI:https://doi.org/10.1897/1551-5028(1998)017<1524:ETOBOM>2.3.CO;2· OSTI ID:1728621

Mccloskey, John T. ^[1]; Schultz, Irvin R. ^[2]; Newman, Michael C. ^[3]

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1. U. S. Fish & Wildlife Service
2. BATTELLE (PACIFIC NW LAB)
3. College of William and Mary in Virginia

In classical pharmacology, oral bioavailability of a toxicant is defined as that fraction of an orally administered dose reaching the systemic circulation of the animal. The present study estimates the bioavailability of methyl mercury in channel catfish (Ictalurus punctatus) by comparing concentrations in the blood through time after oral and intra-arterial (IA) administration. Catfish were cannulated in the dorsal aorta and gavaged a pelleted feed, that had been spiked with methyl mercury. Each catfish was gavaged an increasing amount of spiked feed. Following oral dosing, serial blood samples were removed for more than 1500 h. One month after removal of the last blood sample, the same fish were injected IA with methyl mercury and serial blood samples were removed for more than 3000 h. The area under the curve of the blood concentration-time curve extrapolated to infinity (AUC0??) was calculated from fish dosed orally and IA using both non-compartmental (trapezoidal) and compartmental methods. Bioavailability was estimated as the ratio of the dose corrected oral AUC0?? to the IA AUC0??. Average bioavailability estimates from this approach were 33% using non-compartmental (range 14-55%) and 29% using compartmental (range 12-42%) methods, and were correlated with the amount of food gavaged to the fish (r2 = 0.95, p = 0.026). Bioavailability estimates using the present methodology were much lower than estimates using more conventional methodologies (i.e. assimilation efficiency estimates using mass balance) suggesting that they might overestimate the true bioavailability of toxicants in fish.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1728621
• Report Number(s): PNWD-SA-5236
• Journal Information: Environmental Toxicology and Chemistry, Journal Name: Environmental Toxicology and Chemistry Journal Issue: 8 Vol. 17; ISSN 0730-7268
• Country of Publication: United States
• Language: English