Inhibition of ketogenesis by ketone bodies in fasting humans

Six obese subjects who had fasted 2 to 23 days received a primed constant intravenous infusion of labeled acetoacetate for 4 hours, followed after a 2 hour control period by unlabeled sodium acetoacetate. The infusion raised total ketone levels by 47 to 92 percent, and endogenous ketone production fell to 67 to 90 percent of control values. Free fatty acids fell by 13.5 percent and glycerol by 17.3 percent, without significant changes in peripheral insulin concentrations.