Lactate for Energy and Neurocognition

The unlabeled lactate infusion cocktail (30% L(+)-lactic acid solution (Sigma) with 2N NaOH, pH4.8) and stable isotope infusions were made by a pharmacy and tested to be sterile and pyrogen free. Upon arriving to the KU Clinical and Translational Science Unit, a catheter will be placed in the subject's hand, which will be placed into a heated hand box for collection of arterialized blood. A second catheter will be placed in the opposing forearm vein for the infusion of lactate isotope solution and unlabeled lactate infusion cocktail. After insertion of the catheters, and prior to isotope infusion, a background blood and breath sample (ParvoMedics TrueOne 2400) will be obtained. We will then administer priming doses of 57.5 mg \[13C3\]lactate, 250 mg D2-glucose and 136 mg H13CO3- followed by continuous infusions of \[13C3\]lactate at 10 mg/min and D2-glucose at 2 mg/min \[53\]. Along with the continuous isotope infusion we will begin infusion of the Na-lact