PROTON NMR OBSERVATION OF GLYCOGEN IN-VIVO

Our previous solution studies of the proton relaxation properties of g lycogen H1 have shown significant dipolar cross-relaxation with intra- ring H2 and inter-ring H4' protons characterized by a correlation time tau(c) = 2.7 x 10(-9) s. This leads to a significant negative Nuclear Overhauser Enhancement (NOE) of glycogen H1 following either transien t or steady state perturbations of the longitudinal magnetization of d ipolar coupled protons, especially H2 and H4'. Here we use the NOE to edit selectively the H1 resonance of glycogen in the rat liver in vivo using a surface coil probe. The approach shows the possibility of mea suring glycogen in vivo with high sensitivity using H-1 NMR.