The language of biological fluids

Abstract

-Glass capillary gas chromatography in combination Wlth mass spectrometry is an efficient tool for the investigation of steroids and acids occurring in biological fluids. Many of the compounds indicated in the gas chromatograms are still unknown. Their structure determination can be done with a combination of microchemical reactions and mass spectrometry.A few examples demonstrate the usefulness of "profiling": Emotional stress cause a 10 -30 fold increase in the excretion of dehydroepiandrosterone (DHEA). An even higher increase in the DHEA excretion is observed in some cases of hirsutism. Physical stress is manifested by an increase in the excretion of citric acid and a decrease in conjugates of amino acids.The main steroid in blood plasma is DHEA. In patients suffering from uremia the main steroid was found to be 3ß,17ß-dihydroxy-5-androstene. INTRODUC TI ONThe human body is a perfect working chemical factory, utilizing food and drink as fuel, and rendering poisonous substances innocuous. The pipeline fluids are blood and CSF, the waste water is urine.Just as a defect in the function of a factory can be spotted by a change in the composition of pipeline fluids and waste water, the qualitative and quantitative composition of the compounds in blood and urine offers us informati~ on about the present state of our body. Such an analysis offers a possibility of recognizing malfunctions of the body in an early stage. In consequence it may provide the basis for repairing the defect.At the moment the language of the metabolites is still obscure, because until quite recently we have not had any methods to analyse such extremely complex mixtures as biological fluids. Only in very few cases were connections between an abnormal excretion of body-produced compounds and malfunctions recognized and used for diagnostic purposes, for instance, by colour tests to diagnose diabetes or phenylketonuria. Nowadays the introduction of powerful Separation techniques like glass capillary gas-chromatography in combination with sensitive and specific identification methods like mass spectrometry, offers the possibility ofinvesngatUglow molecular weight metabolites and thus enables us to learn more about the language of body fluids. WORK-UP PROCEDUREBiological fluide are extremely complex mixtures containing compounds in very different relations. For instance in blood the amount of cholesterol (1) and its esters is about 1000-times higher than that of dehydroepiandrosteröne (2), the next most abundant steroid. The total amount of all other steroids isonly 2/3 of that of dehydroepiandrosterone -and these are the interesting ones.