Alison Sleigh1, Philippa Raymond-Barker2, David Porter3, Kerrie Thackray4, Louise McGrath1, Soren Brage4, Mensud Hatunic4, T. A. Carpenter1, Kevin M. Brindle5,6, Graham J. Kemp7, Steve O'Rahilly4, Rob K. Semple4, David B. Savage4
1Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, United Kingdom; 2Wellcome Trust Clinical Research Facility, Addenbrooke's Hospital, Cambridge, United Kingdom; 3Siemens AG Healthcare Sector, Erlangen, Germany; 4Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom; 5Dept. of Biochemistry, University of Cambridge, Cambridge, United Kingdom; 6Cancer Research UK Cambridge Research Institute, Cambridge, United Kingdom; 7Magnetic Resonance & Image Analysis Research Centre, University of Liverpool, Liverpool, United Kingdom
We use 31P-MRS at rest (saturation transfer technique), and post exercise (PCr recovery rate), in subjects with congenital severe insulin resistance due to loss-of-function mutations in the INSR gene. PCr recovery post exercise is significantly slowed in the INSR patients suggesting that primary congenital insulin resistance can precede mitochondrial dysfunction. Resting ATP synthesis rate (ST VATP) measured from the saturation transfer method did not differ significantly between groups. This is consistent with recent findings in rats, which support concerns over its validity in accurately measuring ATP synthesis rates. We found no significant correlation between ST VATP and PCr recovery rate.