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Exercise training alters aortic vascular reactivity in hypothyroid rats
M D Delp1, R M McAllister, M H Laughlin
1Department of Surgery, Medical College of Pennsylvania, Pittsburgh, USA.
The American Journal of Physiology
|April 1, 1995
Summary
Hypothyroidism impairs arterial vessel sensitivity to vasoconstrictors and reduces vasodilator function in rats. Exercise training partially restores these vasomotor responses in hypothyroid animals.
Area of Science:
- Cardiovascular Physiology
- Endocrinology
- Exercise Physiology
Background:
- Hypothyroidism is known to cause cardiovascular changes, including reduced blood flow to skeletal muscle and increased peripheral resistance.
- Exercise training typically improves blood flow and reduces vascular resistance.
Purpose of the Study:
- To investigate how hypothyroidism affects arterial vasomotor responses.
- To determine if exercise training can modify these hypothyroidism-induced vascular changes.
Main Methods:
- Rats were grouped into sedentary euthyroid, sedentary hypothyroid, and exercise-trained hypothyroid.
- In vitro studies on abdominal aortic rings examined responses to vasoactive compounds.
- Vessel sensitivity and maximal contractile/vasodilator responses were measured.
Main Results:
- Hypothyroidism decreased arterial sensitivity to vasoconstrictors like KCl and norepinephrine (NE).
- Maximal vasodilator responses to acetylcholine were reduced in hypothyroid rats but improved with exercise training.
- Vasodilator responses to sodium nitroprusside and forskolin were altered under specific preconstriction conditions.
Conclusions:
- Hypothyroidism significantly alters arterial vasomotor function, decreasing sensitivity to vasoconstrictors and impairing vasodilation.
- Exercise training demonstrates a potential to partially ameliorate these detrimental vascular effects of hypothyroidism.