title: Contractility of the ovarian vascular bed during the oestrous cycle and early pregnancy in gilts.
abstract: The vasoconstrictor activity of the ovarian vascular bed in vitro was investigated during the oestrous cycle and early pregnancy. Gilts were killed during the follicular phase (Days 20 to +1; N = 5) or luteal phase (Days 11 to 13; N = 4) of the oestrous cycle, or on Day 13 of pregnancy (N = 5). Immediately before death, a sample of vena cava blood was obtained for determination of progesterone and oestrogen (oestrone and oestradiol-17 beta) concentrations. One ovary was removed, cannulated, perfused in vitro, and subjected to 10-min infusions of saline (vehicle control) and noradrenaline. Vasoconstriction was provoked by electrical stimulation at the end of each infusion. Ovaries from luteal-phase gilts exhibited greater (P less than 0.01) vasoconstriction than did ovaries from follicular-phase and pregnant gilts at the end of saline and noradrenaline infusions. The oestrogen to progesterone ratio was less (P less than 0.01) for luteal-phase and pregnant than for follicular-phase gilts. Vasoconstriction was negatively correlated (r = -0.99, P less than 0.01) with the oestrogen to progesterone ratio in systemic blood of gilts during the oestrous cycle but not during early pregnancy (r = +0.39, P greater than 0.10), possibly due to an effect of the conceptuses.
mesh_terms: D000818:Animals; D004558:Electric Stimulation; D004958:Estradiol / Q000097:blood; D004970:Estrone / Q000097:blood; D004971:Estrus; D005260:Female; D006439:Hemodynamics; D010053:Ovary / Q000098:blood supply*; D010477:Perfusion; D011247:Pregnancy; D011270:Pregnancy, Animal; D011374:Progesterone / Q000097:blood; D013552:Swine
chemical_list: D004970:Estrone; D011374:Progesterone; D004958:Estradiol