Steroid hormones in blood and tissue

Advances in GC separation and ionization detection techniques during the 1960 s generated a great deal of interest and justifiable excitement for endocrinologists, due to the new possibilities of following hormones and their metabolites in body circulation. In particular, the development of electron-absorbing derivatives 

In order to understand the dynamics of hormone production, secretion, and its effects on the target tissues, high-sensitivity measurements in blood and tissues are required. Because the levels of circulating hormones are generally low and the volumes of blood or tissue available for the analysis tend to be small, subnanogram-level determinations are necessary. The sensitivity of many ionization detectors, including the flame ionization detector and the electron-capture detector, do have this capability. 

However, the measurement specificity is yet another important consideration in assuring the desired results conventional GC detectors can hardly satisfy this criterion if the measurements are performed in crude biological extracts. In this view, it is hardly surprising to read the statement by Adlercreutz and Luukkainen 

Indeed, many such laboratories have performed urinary analyses of hormone metabolites rather than plasma measurements. While the urinary metabolite determinations may provide valuable information of its own, it is often argued that they are not entirely representative of the hormonal secretion due to a variety of reasons (incompleteness of sample collection, altered renal function, multiple metabolic sources of a urinary metabolite, etc.). 

After the successful development of the radioimmunoassay [276,277], enzyme immunoassay [278] and competitive protein-binding methods [279,280] for most hormones of interest, it was generally felt that the necessary clinical criteria of precision, accuracy, specificity and sensitivity can be met without the tedious GC methods. However, this notion has been challenged more recently. While such techniques are undoubtedly more useful with considerably larger molecules, cross-reactivity [283] toward molecules as similar, structurally, as testosterone and 5a-dihy-drotestosterone is regularly observed. Thus, unless the tedious purifications are once 

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