Search results
Results from the WOW.Com Content Network
In vertebrates, gluconeogenesis occurs mainly in the liver and, to a lesser extent, in the cortex of the kidneys. It is one of two primary mechanisms – the other being degradation of glycogen (glycogenolysis) – used by humans and many other animals to maintain blood sugar levels, avoiding low levels (hypoglycemia). [2]
If the blood glucose level falls to dangerously low levels (as during very heavy exercise or lack of food for extended periods), the alpha cells of the pancreas release glucagon, a peptide hormone which travels through the blood to the liver, where it binds to glucagon receptors on the surface of liver cells and stimulates them to break down glycogen stored inside the cells into glucose (this ...
If the blood glucose level drops lower than this, especially to dangerously low levels, release of hyperglycemic hormones (most prominently glucagon from islet of Langerhans alpha cells) forces release of glucose into the blood from the liver glycogen stores, supplemented by gluconeogenesis if the glycogen stores become depleted. By increasing ...
In animals, this is a rate-controlling step of gluconeogenesis, the process by which cells synthesize glucose from metabolic precursors. The blood glucose level is maintained within well-defined limits in part due to precise regulation of PEPCK gene expression.
High blood-glucose levels, on the other hand, stimulate the release of insulin. Insulin allows glucose to be taken up and used by insulin-dependent tissues. Thus, glucagon and insulin are part of a feedback system that keeps blood glucose levels stable. Glucagon increases energy expenditure and is elevated under conditions of stress. [4]
The action of insulin is counterregulated by glucagon, epinephrine (), norepinephrine (noradrenaline), cortisol, and growth hormone.These counterregulatory hormones—the term is usually used in the plural—raise the level of glucose in the blood by promoting glycogenolysis, gluconeogenesis, ketogenesis, and other catabolic processes. [1]
Hypoglycemia, also called low blood sugar or low blood glucose, is a blood-sugar level below 70 mg/dL (3.9 mmol/L). [ 3 ] [ 5 ] Blood-sugar levels naturally fluctuate throughout the day, the body normally maintaining levels between 70 and 110 mg/dL (3.9–6.1 mmol/L).
Ketotic hypoglycemia refers to any circumstance in which low blood glucose is accompanied by ketosis, the presence of ketone bodies (such as beta-hydroxybutyrate) in the blood or urine. This state can be either physiologic or pathologic; physiologic ketotic hypoglycemia is a common cause of hypoglycemia in children, often in response to ...