Endocrine System Evaluation in Rats

This study is designed for a test substance which has shown some effects on endocrine systems during me preceding toxicology evaluation (28 days treatment in rats, or in dogs), however without a distinct profile related to a specific endocrine system. 

The duration of me treatment period should be at least seven days. It may be extended to the duration of a preceding toxicology study (28 days) where some observations for concem-were made, but no satellite groups were included for specific investigation. 

At the end of me treatment period, groups of animals are killed under minimum stress conditions, preferably by rapid decapitation. The time point 24 hours after last dosing is not always suitable, e.g. when changes in pituitary hormone contents need to be assessed, the time point 2 hours after last dosing is preferable. Satellite groups need to be included if necessary for me exact time course of changes after dosing. 

Pituitary-adrenal axis Pituitary weight Adrenal weight Thymus weight 

Pituitary-thyroid axis Pituitary weight Thyroid weight 

---