Summary An association between corpora lutea and physiological responses of the vascular smooth muscle of the utero-ovarian arteries was demonstrated. Arteries serving the ovaries bearing corpora lutea responded to norepinephrine, epinephrine, and serotonin with significantly greater changes in perfusion pressure than did the arteries associated with ovaries not having a luteal body. Vasoconstrictor responsiveness to periarterial sympathetic nerve stimulation agreed with these findings. In addition, baseline perfusion pressures were elevated for the arteries from the side adjacent to the ovary with the corpus luteum compared to values for the arteries from the other ovary. The arteries removed during the luteal phase (Day 13) of the estrous cycle, however, did not elicit significantly greater responses to vasoactive biogenic amines than the arteries removed at the time of ovulation (Day 0).