Vascular effects of vasopressin an oxytocin in the pig mesenteric bed.

The influence of intraarterial infusions of lysine-vasopressin and oxytocin on mesenteric vascular resistance has been studied in anaesthetized young pigs. Vasopressin provokes a pronounced vasoconstrictor effect, whereas oxytocin induces a biphasic response: a transient vasodilation, followed by a more pronounced and sustained vasoconstriction. The comparison of the plasma concentrations of these hormones during parturition and hemorrhage in the pig with the minimal effective doses infused, suggests a possible mesenteric vasoconstrictor effect of oxytocin during parturition and of lysine-vasopressin during hemorrhage.