Uterine blood flow during the development and regression of the decidual cell reaction in ovariectomized, steroid-treated mice.

Uterine blood flow was assessed in mice by measuring organ uptake of intravenously injected [14C]butanol. In ovariectomized mice, injection of 100 ng oestradiol-17 beta increased blood flow 5-fold over that of untreated controls. The injection of oestradiol-17 beta in progesterone-treated mice also increased uterine blood flow at the time of maximal sensitivity to a decidual stimulus, but not 4 days later. Absolute values of blood flow increased during development of the decidual cell reaction in proportion to the increase in uterine weight, reaching maximal values 96 h after decidual induction. When progesterone injections were stopped 72 h after decidual induction, a rapid decrease in absolute and relative blood flow values preceded the decrease in uterine weight. This decrease in uterine blood flow occurred within 12 h of removing a subcutaneous implant containing progesterone. These results are consistent with the view that increased uterine blood flow during decidual development may be necessary to support the rapid increase in uterine weight at implantation and the subsequent decrease in both relative and absolute uterine blood flow on withdrawal of progesterone may promote decidual regression in the mouse.