FIG. 4.

Effect of pregnancy on the ratio of Ca²⁺-induced contractions to MLC₂₀-P in β-escin-permeabilized uterine arteries in long-term, high altitude hypoxic sheep. β-escin-permeabilized uterine arteries from nonpregnant and pregnant ewes acclimatized to high altitude hypoxia were stimulated with increasing concentrations of Ca²⁺. MLC₂₀-P and contractions were measured simultaneously in the same tissues. Data are means ± SEM of tissues from 6 to 7 animals. *p < 0.05 versus nonpregnant animals; †p < 0.05 versus 3 μmol/L Ca²⁺.