Real-Time In-Organism NMR Metabolomics Reveals Different Roles of AMP-Activated Protein Kinase Catalytic Subunits.

AMP-activated protein kinase (AMPK in human and AAK in ) is a master regulator of metabolism. It has many isotypes, but its isotype-dependent functions are largely unknown. By developing real-time in-organism NMR metabolomics for , we were able to study different roles of the isotypic catalytic subunits of AAK/AMPK, AAK-1, and AAK-2 in live worms at the whole organism level. The knockout animals exhibited enhanced glucose production under starvation, strikingly opposite to knockout animals. Unusually high compensatory expression of the reciprocal isotypes in each KO strain and the results for the double KO animals suggested an unconventional phenotype-genotype relationship and the dominance of in glucose production. The gene expression patterns showed that the differential phenotypes of KO strain are due to reduced TCA and glycolysis and enhanced gluconeogenesis compared to the KO strain. Subsequent C-isotope incorporation experiment showed that the glucose production in KO occurs through the activation of fatty acid oxidation and glyoxylate shunt. Revealing differential roles of the isotypes of AAK/AMPK, our convenient approach is readily applicable to many models for human metabolic diseases.