The Measurement of Estrogens

Abstract

Biologists use the word ‘estrogen’ when referring to molecules which have the ability to induce uterine growth or vaginal cornification in the immature or ovariectomized rodent. The word estrogen was derived from two Greek words – oistros meaning frenzy and gennein – to beget. Chemists and biochemists, however, often restrict their use of this term to molecules that contain a characteristic 18-carbon steroid nucleus with an aromatic (phenolic) A-ring, both those that are biologically active estrogens and those without biologic activity but which are of intrinsic interest, such as the estrogen conjugates. This chapter is concerned only with these steroid compounds. The structure and inter-relationship of some common estrogens are given in Fig. 8.1. In addition to the biological estrogens, there are a wide variety of both natural and synthetic compounds which have estrogenic activity when measured by one or another parameter. While many of the assay procedures described in this review are applicable to these compounds, their application to non C18-steroids will not be discussed here. Methodology for these non-steroidal compounds can be found in reviews by Wang et al. (2002), Wu et al. (2004), Muir (2006), and Delmonte and Rader (2006). While not wishing to downgrade the importance of previous work in the estrogen field, the authors have taken a deliberate decision to exclude most publications prior to 1975, not because these do not have value but simply because space is not unlimited and readers of the present chapter might be expected to be seeking information about methodology which is less than 30 years old. Readers seeking pre-1975 information in this area can find it in Oakey and Holder (1995).