Toxicokinetics and molecular interaction of [14C]-formaldehyde in rats

Raj K. Upreti, Mohammed Y.H. Farooqui, Ahmed E. Ahmed, G. A.S. Ansari

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18 Scopus citations


The excretion, tissue distribution, and binding of [14C]-formaldehyde were studied at different time intervals in male rats following a single intraperitoneal injection of 72 mg CH2O (14.7 μCi)/ kg body weight. Within 30 min, 10% of the total dose was recovered in expired air as14CO2 and by the end of 72 hr, 41% of the administered dose was eliminated through expired air. The total elimination of14CH2O activity in urine and feces in 72 hr was 15%. Erythrocytes retained significant amounts of radioactivity, even at the end of 72 hr. Substantial levels of radioactivity were detected in most tissues one hr after administration, indicating a fast absorption and rapid distribution. Subcellular fractionation of the tissues showed that the highest levels of relative percent binding was in the microsomal fraction, whereas cytosol fractions contained lowest levels of bound radioactivity. DNA, RNA, protein and lipid fractions of liver and spleen tissues showed significantly elevated levels of14C-incorporation as compared to other tissues. The in vivo incorporation of14C-activity showed an increased association of14CH2O with RNA in all the tissues. The maximum registration of radioactivity in RNA was at 48 hr after administration. Significantly higher amounts of14C-activity were registered in DNA of all tissues. The maximum registration of radiolabel in DNA of most tissues was at 12 hr after the14CH2O administration. The liver DNA showed maximal levels at 3 hr with a second peak at 48 hr. Substantial amounts of bound radioactivity in nucleic acids of all the tissues were observed even 72 hr after dosing. The relationship between macromolecular association and formaldehyde toxicity has been discussed.

Original languageEnglish (US)
Pages (from-to)263-273
Number of pages11
JournalArchives of Environmental Contamination and Toxicology
Issue number3
StatePublished - May 1987
Externally publishedYes

ASJC Scopus subject areas

  • Toxicology
  • Pollution
  • Health, Toxicology and Mutagenesis


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