Rat lung hexokinase: some aspects of the metabolic and hormonal regulation of its subcellular distribution.

Addition of glucose-6-phosphate (0.03-0.06 mM) to a suspension of rat lung mitochondria promotes solubilization of 30 to 85% of the bound form of hexokinase. This effect is significantly enhanced by the simultaneous addition of glucose (10 mM), fructose (10 mM) or mannose (10 mM). Conversely addition of N-acetylglucosamine (10 mM), mannose-6-phosphate (10 mM) or inorganic phosphate (1 mM) reduces hexokinase solubilization. Insulin is involved in the regulation of the interaction between mitochondrial membrane and hexokinase. Treatment with alloxan causes an increase of the free form of the enzyme in the lung and a correspondent reduction of the bound form. Insulin administration restores the normal intracellular distribution of the enzyme.