1. ¹Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
2. ²Oregon Health Sciences University, Portland, Oregon, USA

Correspondence: Associate Professor MT Littleton-Kearney, Department of Anesthesiology/Critical Care Medicine, Johns Hopkins Medical Institutions, 600 N. Wolfe St., Blalock 1404-C, Baltimore, MD 21287, USA. E-mail: mkearney@jhmi.edu

Received 30 July 2004; Revised 26 August 2004; Accepted 22 September 2004; Published online 2 February 2005.

Abstract

The reason that estrogen is strongly protective in various estrogen-deficient animal models while seemingly detrimental in postmenopausal women remains unclear. It hypothesized that prolonged oral medroxyprogesterone (MPA) plus oral conjugated equine estrogens (CEE) diminishes estrogen ability to reduce stroke damage in the rodent stroke model. To test the hypothesis, we fed ovariectomized rats CEE or MPA, or a combination of CEE and MPA (CEP), before inducing 120 min of reversible focal stroke, using the intraluminal filament model. After 22 h reperfusion, the brains were harvested and infarction volumes were quantified. Treatment with CEE alone or with CEP reduced cortical infarction volume. However, CEP failed to provide ischemic protection in subcortical regions. It was concluded that CEE alone, or with CEP, is neuroprotective in the cortex, but interactive effects between the hormones may counteract CEE beneficial effects in subcortical brain regions.