Deck 1: Biological Research in Toxicology

Question 1

Why are malformations of amphibians insufficient evidence for chemical toxicity?

Answer 1

Malformations may come from parasites and other influences that are not necessarily related to pollutants. Also a one low concentration effect of a compound like atrazine does not mean that malformations found in the wild are due to that agent.

Question 2

How is toxicogenomics a form of cellular toxicology?

Answer 2

Toxicogenomics involves changes in DNA structure, expression and translation into protein (via mRNA transcription and tRNA/ribosomal protein synthesis) that are cellular functions of the nucleus (for eukaryotic organisms) and the cytoplasm/endoplasmic reticulum. A cancer cell may indeed by one aberrant cell whose genomics has been sufficiently altered to be a grave danger to the entire organism but started as a focus.

Question 3

What toxicological information does the whole organism give toxicologists as exemplified by the injection of ¹⁴C -labeled esophageal carcinogen N-nitrosomethylbenzylamine?

Answer 3

The distribution and activation by biotransformation was highest in the target organ which cannot be determined by exposing just one cell fraction from one tissue.