Ici 182 780 ici

A group of four male Sprague-Dawley rats (250–300 g, Charles River, Wilmington, MA, USA) were implanted with subcutaneous osmotic pumps (Alzet, Cupertino, CA, USA) containing E2 released at a flow rate of 75 µg/kg/day for three weeks. This dose results in E2 levels equivalent to physiological concentrations in adult female Sprague-Dawley rats.^{18 (link)} An additional group of four male rats were implanted with E2 osmotic pumps and concomitantly administered the non-selective ER-antagonist ICI 182,780 (ICI; Tocris, Bristol, UK) daily via subcutaneous injection (3 mg/kg/day). Following one week of recovery, E2, E2 + ICI treated rats, and four male hypoxic control rats were exposed to two weeks of hypobaric hypoxia (P_atm = 362 mmHg; equivalent to 10% FiO₂ at sea level) as described previously^{20 (link)} (Supplemental Fig. 1). An additional four male rats were used as normoxic controls. All animals were part of a larger study in which we demonstrated that E2 ER-dependently attenuates HPH.^{20 (link)} Hemodynamic, structural, and biochemical characteristics of the experimental groups were described previously.^{20 (link)} Four animals from each group were randomly selected for microarray studies. Vehicle controls for E2 and ICI were tested in prior studies and found not to have any effects on cardiopulmonary parameters^{20 (link)} (and were therefore not included in the current analysis).