Method for selecting exposure levels for the Drosophila sex-linked recessive lethal assay
The use of the Drosophila sex-linked recessive lethal assay for detecting mutagenicity of chemicals is well established. When compounds are tested by feeding adult flies, the National Toxicology Program protocol specifies a 3-day feeding regimen at an exposure level that produces about 30% mortality. Uptake of the test compound is monitored by feeding behavior, amount of excretion, or abdomen size. An alternate method for determining uptake is to add radiolabeled sucrose to the feeding solution and then to determine the amount of radioactivity in the flies. We have found that the addition of radiolabeled sucrose underestimates consumption for feeding exposures longer than 24 hr because sucrose is metabolized and as much as 30% of the label is excreted, presumably as /sup 14/CO/sub 2/ or /sup 3/H/sub 2/O. Here we describe a method for determining uptake of chemicals by adding /sup 14/C-leucine to the feeding solution. The incorporation of /sup 14/c-leucine is essentially linear over the 3-day feeding period, which permits accurate estimates of food consumption. Use of this method demonstrates that lower exposure levels of a chemical that do not produce mortality actually results in higher consumption by the flies. The method is proposed as a prescreen to select the appropriate exposure level for the sex-linked recessive lethal assay.
- Research Organization:
- Procter and Gamble Company, Cincinnati, OH
- OSTI ID:
- 5605946
- Journal Information:
- Environ. Mol. Mutagen.; (United States), Vol. 10:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
XENOBIOTICS
MUTAGEN SCREENING
CARBON 14 COMPOUNDS
DROSOPHILA
FOOD
GENES
LEUCINE
METABOLIC ACTIVATION
MUTAGENS
SACCHAROSE
TRACER TECHNIQUES
TRITIUM COMPOUNDS
AMINO ACIDS
ANIMALS
ARTHROPODS
CARBOHYDRATES
CARBOXYLIC ACIDS
DIPTERA
DISACCHARIDES
FLIES
FRUIT FLIES
INSECTS
INVERTEBRATES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
OLIGOSACCHARIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
SACCHARIDES
SCREENING
560300* - Chemicals Metabolism & Toxicology
550501 - Metabolism- Tracer Techniques