Time course of the changes in uterine vascular permeability associated with the development of the decidual cell reaction in ovariectomized steroid-treated rats.

Uterine vascular permeability and tissue blood volume during the development of the oil-induced decidual cell reaction (DCR) in ovariectomized steroid-treated rats were assessed by measuring the extravascular accumulation of 125I-labelled human serum albumin and the tissue content of 51Cr-labelled red cells 30 min after intravenous administration. Within 15 min of oil instillation into one uterine horn, the vascular permeability of the horn was significantly elevated. Permeability rose to a sharp peak (10 times control levels) 9 h after oil instillation, but dropped to 5 times control values by 12 h and continued a steady decline over the next 7 days. Although a marked increase in uterine weight was associated with the development of the DCR, there was no significant change in blood volume/g tissue until 4 days after oil instillation.