The endocrine regulation of uterine blood flow in the nonpregnant uterus: a review.

Evidence is presented to demonstrate the role of steroid hormones in the regulation of blood flow through the nonpregnant uterine vasculature. Estrogens appear to increase blood flow, as documented by the observed increases in flow during proestrus and estrus, as well as the response to exogenous hormone stimulation in laboratory animals. The mechanism for the stimulation of blood flow is apparently indirect, and mediated by another vasoactive agent(s) which remains unknown at this time. Conversely, progesterone decreases estrogen-induced uterine blood flow, probably by depleting the amount of available cytoplasmic estrogen receptor.