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The thyroid in the spontaneously hypertensive rat: a light and electron microscopic study
The American Journal of Anatomy
|April 1, 1977
Summary
Spontaneously hypertensive rats exhibit thyroid ultrastructural changes, suggesting impaired thyroid hormone synthesis and secretion. Their thyroids do not adequately respond to elevated thyroid-stimulating hormone levels.
Area of Science:
- Endocrinology
- Pathology
- Hypertension Research
Background:
- Spontaneously hypertensive rats (SHR) often display thyroid function abnormalities.
- Understanding these changes is crucial for comprehending hypertension-related endocrine disruptions.
Purpose of the Study:
- To investigate ultrastructural alterations in the thyroid gland of SHR.
- To correlate these changes with thyroid function and blood pressure.
Main Methods:
- Light and electron microscopy were used on Wistar Kyoto rats (WKY) and SHR.
- Plasma triiodothyronine (T3) levels and systolic blood pressure were measured.
- Effects of propylthiouracil (PTU) administration were assessed.
Main Results:
- SHR had significantly higher systolic blood pressure than WKY, but similar plasma T3 levels.
- Thyroid follicles in SHR were variable in size, with colloid abnormalities.
- SHR thyroids showed impaired response to endogenous thyroid-stimulating hormone (TSH) but responded to PTU-induced TSH elevation.
Conclusions:
- The thyroid gland in SHR may have defects in thyroid hormone synthesis and/or secretion.
- This impairment likely contributes to thyroid dysfunction in hypertensive states.
- Ultrastructural findings provide insights into the thyroid's inadequate response to TSH in SHR.