Reciprocal regulation of glycolysis and gluconeogenesis:

Glycolysis generates two ATPs net per glucose while gluconeogenesis uses four ATPs and two GTPs per glucose. Therefore, if both glycolysis and gluconeogenesis  were  permits  to  operate  concurrently,   converting  glucose  to back again   and  pyruvate the only net result  would  be the utilization  of two ATPs  and two GTPs, a so-called futile cycle. This is avoided through tight coordinate regulation of gluconeogenesis and glycolysis. Since several of the steps of the two pathways are general, the steps which are distinct in each pathway are the sites of this regulation, in particular the interconversions among fructose 1, 6-bisphosphate   and fructose 6-phosphate and among PEP and pyruvate.