Thyroid State and Vascular Reactivity in Rats.

Summary The sensitivity of resistance vessels to the action of norepinephrine and angiotensin in hypothyroid, hyperthyroid, and euthyroid states was determined using auto-perfused rat hindquarter preparations. The vasoconstrictor responses were adjusted for perfusion pressure using analysis of covariance. Hypothyroid animals were more responsive to the vasoconstrictors than euthyroid controls. The responsiveness to angiotensin was unaltered in hyperthyroid rats but the sensitivity to norepinephrine was slightly reduced.