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Updated: Jul 29, 2026
An Ex vivo Culture System to Study Thyroid Development
Published on: June 6, 2014
Development of home orientation in hypothyroid and hyperthyroid rat pups
Insights
Perinatal hypothyroidism delayed but did not prevent the development of the home orientation response in pups. This suggests that thyroid hormone
Area of Science:
- Neuroscience
- Developmental Biology
- Endocrinology
Background:
- Thyroid hormones are crucial for normal brain development and function.
- Perinatal thyroid dysfunction can lead to long-term neurodevelopmental deficits.
- The home orientation response is a complex behavior essential for infant survival.
Purpose of the Study:
- To investigate the impact of perinatal hypothyroidism and hyperthyroidism on the development of the home orientation response.
- To assess the effects of thyroxine replacement therapy on pups with induced thyroid dysfunction.
Main Methods:
- Hypothyroidism was induced using propylthiouracil in pregnant/lactating dams.
- Hyperthyroidism and replacement therapy were achieved via daily thyroxine injections.
- The home orientation response was assessed in pups from Day 4 to Day 22 postpartum.
Main Results:
- Hyperthyroid, control, and thyroxine-treated pups exhibited similar home orientation response development, peaking between Days 12-16.
- Hypothyroid pups showed a delayed peak in home orientation response until Day 20.
- Despite the delay, the overall percentage of hypothyroid pups successfully homing was comparable to other groups.
Conclusions:
- Perinatal hypothyroidism can delay the emergence of integrated behavioral responses, such as home orientation.
- The home orientation response can still develop and appear intact at a later age despite earlier thyroid hormone deficiency.
- Thyroid hormone levels during the perinatal period significantly influence the timing of behavioral development.
Abstract:
In order to assess the effects of perinatal hypothyroidism or hyperthyroidism on the development of an integrated behavioral response, we tested hypothyroid, hyperthyroid, and control pups, as well as pups receiving thyroxine replacement therapy, for the development of the home orientation response. Hypothyroidism was induced in the pups by feeding the pregnant or lactating female a diet of .2% propylthiouracil from Day 15 of gestation to Day 22 postpartum. Pups receiving replacement therapy and pups made hyperthyroid were injected daily with thyroxine, starting at birth. The ability of the pups to initiate and maintain locomotion toward the nest was assessed between Days 4 and 22. Hyperthyroid, control, and replacement therapy pups behaved very similarly on the task, showing a peak in the percentage of pups homing between Days 12 and 16. Hypothyroid pups showed a delay in the peak percentage until Day 20, although the percentage of pups was similar to that found in other treatments. An integrated behavioral response can be delayed by hypothyroidism and still emerge apparently intact at a later age.
