Decidua-associated changes in guinea pig uterine blood flow and volume: relation to uterine norepinephrine concentrations.

Changes in uterine blood flow (UBF) and uterine blood volume (UBV) during decidual tissue (DT) formation in the guinea pig were assessed at 2, 6, and 10 days postuterine trauma (PT). Uterine weight increased steadily between days 2 and 10 PT in DT-bearing animals as compared with the constant uterine weights observed in controls. Both UBF and UBV levels were elevated between days 2 and 10 PT in DT-bearing animals as compared with controls with the vascular changes being histologically related to the progressive stromal differentiation. Uterine norepnephrine (NE) levels were significantly (P less than or equal to 0.05-0.01) depressed in the hyperemic, DT-bearing uteri as compared with controls. These results indicate that the uterine hyperemia associated with DT formation in the guinea pig involves a sustained increase in uterine vascular volume as well as vascular perfusion rate under conditions of depressed uterine NE levels. These events are intimately associated with the support of stromal differentiation in the guinea pig.