Table of Contents
Why aldolase deficiency is more severe in fructose metabolism and causes hypoglycemia?
In individuals deficient in aldolase B activity, this causes an accumulation of fructose-1-phosphate, leading to subsequent inhibition of both glycolytic and gluconeogenesis pathways, thus causing hypoglycemia in individuals.
Why does fructose-1-phosphate inhibit Glycogenolysis?
Fructose-1-phosphate is a competitive inhibitor of phosphorylase, an enzyme that regulates the conversion of glycogen to glucose. With high levels of fructose-1-phosphate, the conversion of glycogen to glucose is decreased, resulting in lactic acidosis and hypoglycemia, which may precipitate seizures.
Does fructose-1-phosphate inhibit Glycogenolysis?
A deficiency of aldolase B results in hereditary fructose intolerance (HFI) in which the substrate of this enzyme, fructose-1-phosphate, accumulates and inhibits gluconeogenesis and glycogenolysis [124].
How does fructose-1-phosphate inhibit gluconeogenesis?
Hypoglycemia results from inhibition of glycogenolysis and gluconeogenesis. It depletes intracellular phosphate reserves which leads to loss of ATP and inhibition of biosynthetic pathways. Symptoms of hereditary fructose intolerance are apathy, drowsiness, sweatiness and tremulousness.
How does fructose intolerance lead to hypoglycemia?
The accumulation of fructose 1-phosphate results in inhibition of other enzymes, namely phosphorylase, liver fructose 1-6 bisphosphate aldolase and fructokinase. This results in impaired glycogenolysis and glyconeogenesis, and may induce hypoglycemia[8].
Why hypoglycemia is a common manifestation in fructose intolerance?
Hypoglycemia after the administration of fructose or sorbitol is due to a block of hepatic glucose release. Our earlier hypothesis of a primary defect in fructose-1-phosphate splitting liver aldolase has been proved by direct enzyme analysis of liver tissue of both patients.
Why does fructose intolerance cause hyperuricemia?
Fructose consumption can contribute to hyperuricemia by stimulating the catabolism of adenine nucleotides.
How does fructose-1-phosphate enter the mainstream of glucose metabolism?
Fructose enters the glycolytic pathway in the liver through the fructose 1-phosphate pathway. There are no catabolic pathways to metabolize galactose, so the strategy is to convert galactose into a metabolite of glucose. Galactose is converted into glucose 6-phosphate in four steps.
What is the difference between fructose intolerance and fructose malabsorption?
Hereditary fructose intolerance should not be confused with a condition called fructose malabsorption. In people with fructose malabsorption, the cells of the intestine cannot absorb fructose normally, leading to bloating, diarrhea or constipation, flatulence, and stomach pain.
Does fructose malabsorption cause hypoglycemia?
After ingesting fructose, individuals with hereditary fructose intolerance may experience nausea, bloating, abdominal pain, diarrhea, vomiting, and low blood sugar (hypoglycemia). Affected infants may fail to grow and gain weight at the expected rate (failure to thrive).
What does fructose malabsorption mean?
Fructose malabsorption, formerly called dietary fructose intolerance, occurs when cells on the surface of the intestines aren’t able to break down fructose efficiently. Fructose is a simple sugar, known as a monosaccharide, that comes mostly from fruit and some vegetables.
Does uric acid increase blood sugar?
The High level of uric acid or hyperuricemia makes oxidative stress by inducing the production of reactive oxygen species (ROS) which interferes the insulin signalling pathway,creates inflammatory state that reduced the insulin sensitivity,blood glucose uptake and metabolism, also reducing the insulin production from …