Metabolomics is the study of the entire complement of all the small molecular weight metabolitesinside an organism of interest. Some metabolites which are routinely assayed in the blood include urea for liver and kidney function, cholesterol for risk of coronary artery disease, and glucose. This can be a difficult task, however, because metobolites differ widely in their chemical characteristics (solubility, charge, MW, etc), and concentrations can differ by many orders of magnitude. 

The interaction of an organism with its environment is essential to its survival. The basis of this interaction is predominantly small molecules. On a molecular level, small molecules both promote, as in nutrients, and challenge, as in toxins, cell viability. Those gene products that interact with small molecules underlie the organism’s ability to adapt to environmental changes and include those that bind, transport, and metabolize small molecules. 

In the future, databases of metabolomic information will be used to establish the relations among metabolite profiles and health status. One will be able to compare the metabolic status of an individual by comparing the results of diagnostics to the reference knowledge base. This knowledge will allow interventions such as drugs to improve health and prevent disease. 

One can already see such an approach being used. For example, metabolic profiling of amino acids and acylcarnitines from blood spots by automated  is a diagnostic tool for errors of metabolism in newborns. 

Lipidomics is a branch of metabolomics in which non-water soluble metabolites are studied in relation to the function of genes and their proteins. Classical methods of lipid analysis utilize the techniques of thin layer chromatography (TLC), HPLC, gas liquid chromatography (GLC), and MS. The recently developed technique of  has allowed almost complete analysis of the lipidome from organic extracts of cells/tissues. 

The complete analysis of lipid metabolites has been applied to investigate the effects of TZDs which are therapeutic agents against type II diabetes. TZDs decrease serum lipid concentrations but these actions are accompanied by lipid accumulation in tissues. In a study by Watkins, an assessment of the lipid metabolome (the concentration of each lipid class and each of its constituent fatty acids) was applied to evaluate the effect of feeding a low does of a TZD on the lipid metabolisms of diabetic mice. Analysis of the results revealed key targets of the actions of the TZD.