Figure 6. Typical in vivo ³¹P MR spectra at rest of the hindleg of four GAMT–/– mice at different stages of Cr supplementation.

A, without supplementation. B, after 24 h of Cr supplementation. C, after 48 h of Cr supplementation. D, after 1 month of Cr supplementation. Peaks for inorganic phosphate (P_i), phosphocreatine (PCr), phosphorylated guanidinoacetate (PGua) and the three resonance positions of ATP (α,β,γ) are visible.