Effects of equine oestrogens on markers of vasoactive function in human coronary artery endothelial cells

A large proportion of the beneficial effects that oestrogens demonstrate on the vasculature are believed to be mediated via direct effects on the vasc ular wall. In this study we compared a number of oestrogenic compounds isol ated from pregnant mare's urine including 17 beta-oestradiol and oestrone, in terms of their abilities to inhibit stimulated endothelin-1 release from normal human coronary artery endothelial cells (CAEC). We also examined th eir ability to stimulate expression of constitutive endothelial nitric oxid e synthase (eNOS) and explored their effects on cellular angiotensin conver ting enzyme (ACE). All the oestrogens tested were able to inhibit serum-sti mulated ET-1 release. Oestrone and 17 alpha-dihydroequilenin failed to sign ificantly affect cellular eNOS levels. 17 beta-oestradiol and oestrone sign ificantly increased cellular ACE levels while 17 beta,Delta(8,9)-dehydroest radiol decreased cellular ACE. We discuss these observations in terms of th eir potential clinical relevance and use as a means of screening novel oest rogen-like compounds. (C) 1999 Elsevier Science Ireland Ltd. All rights res erved.