Recent insights into the varying activity of estrogens

Recent advances have added substantially to our understanding of the biolog y of estrogens. Estrogens are no longer considered to differ only in potenc y. Two estrogens can have similar effects in one tissue and very different effects in another. Additionally, an estrogen can have different effects in different tissues. It is now recognized that there are at least two estrog en receptors, ER-alpha and ER-beta, and that it is quite likely that estrog ens also work through non-genomic mechanisms. The development of new method s of chromatographic separation has aided substantially in our ability to c haracterize the composition of Premarin, including the identification of es tradiene, the fourth-most abundant estrogen in Premarin. Recent studies hav e contributed to our understanding of the unique profile of Delta(8,9) dehy droestrone sulfate, another of the Premarin estrogens. It was found that De lta(8,9) dehydroestrone sulfate is an active estrogen with a distinct pharm acological profile that results in significant clinical activity in vasomot or, neuroendocrine and bone preservation parameters. However, it displayed little or no efficacy, at the dose studied, on other peripheral parameters normally affected by classical estrogens. Increasing knowledge of the uniqu e profiles of the Premarin components, as well as their complex interaction , will help to increase our understanding of the clinical profile of Premar in. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.