Abstract
Many studies have shown that estrogen increases the blood flow to the pregnant and non-pregnant uterus (1-3), but the mechanism by which this vasodilation occurs has not been determined.
It has been postulated that prostaglandins may mediate this vasodilation. Prostaglandins have been shown to play a role in the regulation of blood flow in the pregnant sheep uterus (4) and some studies have indicated that prostaglandins affect blood flows in non-pregnant uteri (5). Some investigators have also reported finding increased prostaglandin synthesis in uterine tissue following estrogen treatment (6, 7).
The following experiment was designed to study the response of the uterine vasculature to estrogen treatment in the rabbit and to determine if prostaglandins are involved in this response through the use of the known prostaglandin synthetase inhibitors, indomethacin and meclofenamate.
Materials and methods.Non-pregnant female New Zealand white rabbits weighing 1.7-3.5 kg were used in this study. Surgery was performed under Nembutal (Abbott Labs) sedation supplemented by local xylocaine (Astra Pharm.). A left ventricular catheter (i.d. 0.0288 mm) was placed via the left carotid artery and a second polyvinyl catheter was inserted 8-10 cm into the left femoral artery. The femoral catheter was then led to the neck incision via a subcutaneous tunnel. The catheters were secured to a packet made of surgical tape and attached to the rabbit's neck. Experiments were performed the following day with the awake animal resting quietly in a restraining cage.
The mean arterial blood pressure of the rabbit was monitored with a Statham P23Db transducer attached to the femoral catheter. Records were made with an R411 Beckman recorder with an EO- 18 oscilloscope display.
Blood flows were determined by the left ventricular injection of 15 micron microspheres (3M Co., New En land Nuclear) labelled with either l09Gd, 113Sn, 85Sr or 46Sc.
Get full access to this article
View all access options for this article.