Regulation of HMP Pathway

The following factors play an important role in regulation of HMP pathway:

a)  The first  reaction of this pathway catalysed by glucose-6-phosphate dehydrogenase is the "rate  limiting" step. This  is mainl7,regulated by  the cytoplasmic levels of NADP+  and NADPH. 

b) High carbohydrate content in the diet accelerates the rate  of  the pathway  by activiting both the dehydrogenases whereas diabetes mellitus  and starvation reverses these  reactions.

c) The HMP shunt  is activated by the increase  in NADP'  in the cytoplasm, which in turn, is due to the oxidation  (utilization)  of NADPH by the synthesis of fatty acids and steroids.

d)  HMP shunt is accelerated due  to  the stimulation of dehydrogenases  by insulin.

e)  Thyroid  hormone  acts  in  the same way by  stimulating glucose-6-phosphate dehydrogenase.