Metabolites are the intermediates and products of metabolism. The term metabolite is usually restricted to small molecules. Metabolites have various functions, including fuel, structure, signaling, stimulatory and inhibitory effects on enzymes, catalytic activity of their own (usually as a cofactor to an enzyme), defense, and interactions with other organisms (e.g. pigments, odorants, and pheromones). A primary metabolite is directly involved in normal “growth”, development, and reproduction. Ethylene is an example of a primary metabolite produced in large-scale by industrial microbiology. A secondary metabolite is not directly involved in those processes, but usually has an important ecological function. Examples include antibiotics and pigments such as resins and terpenes etc. Some antibiotics use primary metabolites as precursors, such as actinomycin which is created from the primary metabolite, tryptophan. There are also examples of sugars that are metabolites, and example of this would be fructose or glucose in the metabolic pathways.
Findings have indicated that the metabolite characteristics of the lesion are valuable for the investigation of underlying differences in malignancy.
In vivo metabolite imaging provides a unique opportunity for the evaluation of spatial and temporal changes in the lesion and surrounding tissue that can be used to direct tissue sampling at the time of resection, as well as for the selection and monitoring of therapy. The lesion-wide data obtained using this approach are synergistic with recent results from genome-wide sequencing and informatics-driven analyses that identify different subtypes of glioma with genetic characteristics.
The ability to infer the mutational status of isocitrate dehydrogenase (IDH) genes through non-invasive MRSI of D-2-hydroxyglutarate (2HG) is an example with strong prognostic implications. This is a significant breakthrough in the realm of cancer diagnostics 1) 2)