Distribution of progesterone in the uterus, broad ligament, and uterine arteries of beef cows.

Samples of uterine horn, broad ligament (mesosalpinx and mesometrium), and uterine artery of ten unilaterally ovulating cows, 12-15 days after mating, were examined for differences in concentration of progesterone. Tissues (mesosalpinx, branches of the uterine artery, anterior uterine horn) adjacent to the ovary bearing the corpus luteum contained significantly greater quantities of progesterone than more distal tissues (mesometrium, uterine artery, posterior uterine horn) on the same side and all tissues on the contralateral side. In tissues on the side ipsilateral to the corpus luteum, a gradient of progesterone existed. Differences in tissue concentrations of progesterone may be the cause of observed differences in uterine physiology in the cow and ewe.