During the first 24 hours of hypoxia induced by the closure of valves, the Fru-6-P/Fru-1, 6.P₂ pathway accelerates. After, the metabolic depression takes place and can be explained by the fall in the intracellular pH value concomitant with the decrease in the Fru-2,6-P₂ levels. Phosphorylation of regulatory enzymes could be considered as a regulatory potential when it is demonstrated the existence of molecules that stimulate receptors of the phenomenon before pO₂ fall.