Measurements of brain creatine metabolism in vivo: magnetic resonance spectroscopy studies of transgenic animals, Neural Metabolism In Vivo.

In vivo magnetic resonance spectroscopy (mrs) of transgenic mice with modified expression of enzymatically active proteins offers an attractive opportunity for non-invasive study of creatine metabolism in the brain as signals of substrates are particularly well-identifiable in mr spectra. This chapter reviews results of studies on mice with alterations in the expression of the enzymes creatine kinase and guanidinoacetate methyltransferase.mrs studies on mice lacking guanidinoacetate methyltransferase have demonstrated metabolic changes comparable to those found in the deficiency of this enzyme in humans, which are (partly) reversible upon creatine feeding. Apart from being a model for creatine deficiency syndrome, these mice are of interest to study fundamental aspects of the biological role of creatine.mrs studies on transgenic mice lacking creatine kinase isoenzymes have contributed to the view that these enzymes are involved in a large high-energy phosphate metabolic energy network, which is highly versatile and dynamically adapts to genotoxic or physiological challenges.keywordscreatine metabolismmr spectroscopytransgenic mice.