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.