FIGURE 1.

T4 induces more pronounced vasorelaxation of rat sural arteries than T3. (A) Original recording of the T4-induced concentration-dependent vasodilation of the sural artery precontracted by the α₁-adrenoceptor agonist methoxamine (MX). (B) Concentration-response relationships to thyroid hormones of the methoxamine-precontracted sural arteries. (C) Concentration-response relationships to T4 of sural arteries precontracted by methoxamine in the presence of 5′-deiodinase inhibitor iopanoic acid (IOP, 100 μM) or its vehicle. For panels (B,C) average active force value for 10-min interval before addition of the first hormone concentration was taken as 100%. Number in parentheses represents the number of animals. *p < 0.05 compared to vehicle group (Repeated Measures ANOVA with Tukey’s post hoc test).