Acute myeloid leukemia (AML) is glutamine addicted cancer. We determined if hyperpolarized pyruvate could be utilized to detect in vivo metabolic changes in AML (OCI-AML3 cell line) bearing mice after CB839 (glutaminase inhibitor) treatment. We found a reduction of pyruvate to lactate conversion after treatment. In vitro analysis of OCI-AML3 reveal that NADH/NAD+ ratio, ATP, hydrogen peroxide levels and respiratory capacity reduce in CB839 treated cells compared to vehicle controls. Our data supports the hypothesis that in AML glutamine generates reducing equivalences by the citric acid cycle and inhibiting this process with CB839 reduces the rate of conversion of pyruvate to lactate.