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Stress produced by gavage administration in the rat
A P Brown1, N Dinger, B S Levine
1Toxicology Research Laboratory, Department of Pharmacology, University of Illinois at Chicago, 1940 W. Taylor Street, Chicago, IL 60612-7353, USA.
Contemporary Topics in Laboratory Animal Science
|February 15, 2001
Summary
Gavage administration of lipid vehicles, like corn oil, in rats can induce a stress response and elevated corticosterone levels, especially at higher volumes. Researchers recommend limiting gavage dose volumes to 10 mL/kg to avoid adverse effects.
Area of Science:
- Toxicology
- Pharmacology
- Animal Physiology
Background:
- Gavage administration is a common route for administering substances in toxicology studies.
- The choice of vehicle can influence study outcomes by inducing physiological responses.
- Understanding vehicle-induced stress is crucial for accurate toxicological assessments.
Purpose of the Study:
- To investigate the relationship between gavage administration of various vehicles and the induction of stress response in rats.
- To assess clinical signs of distress and aspiration following gavage.
- To determine the impact of vehicle type and volume on plasma corticosterone levels.
Main Methods:
- Male CD rats were administered various vehicles (water, corn oil, methylcellulose/Tween 80, other oils) via gavage.
- Plasma corticosterone levels were measured 1 hour post-dosing.
- Necropsies were performed 4 hours post-dosing to assess pulmonary changes.
Main Results:
- Gavage administration of corn oil at 20 mL/kg induced a stress response (elevated corticosterone) in a volume-dependent manner.
- Aspiration occurred with water and methylcellulose/Tween 80 at 20 mL/kg, but not with corn oil.
- Lipid-based vehicles (corn, sesame, soybean, peanut oils) induced stress responses, unlike water or methylcellulose/Tween 80.
Conclusions:
- Gavage dosing of lipid vehicles activates the stress response in rats, indicated by increased corticosterone.
- The stress response and potential aspiration are dependent on vehicle type and dose volume.
- Recommended gavage dose volumes in rats should generally not exceed 10 mL/kg to mitigate stress and aspiration risks.
