 The major source of NADPH in animals and other non-photosynthetic organisms is the pentose phosphate pathway, by glucose-6-phosphate dehydrogenase (G6PDH) in the first step.The pentose phosphate pathway also produces pentose, another important part of NAD(P)H, from glucose.Some bacteria also use G6PDH for the Entner–Doudoroff pathway, but NADPH production remains the same.