Hormones that control of glucose homeostasis
Hormone
|
Mechanism of action
|
Tissue
|
Insulin
|
Increases: glucose uptake by cells
glycogen synthesis
protein synthesis
synthesis of fatty acids and triglycerides
decreases: gluconeogenesis
ketogenesis
lipolysis
proteolysis
|
Muscle, fat
Liver, muscle
Liver, muscle
Liver, adipose tissue
Liver
Liver
fatty tissue
Muscles
|
glucagon
|
Increases: glycogenolysis
gluconeogenesis
ketogenesis
lipolysis
|
Liver
Liver
Liver
fatty tissue
|
Adrenalin
|
Increases: glycogenolysis
lipolysis
|
Liver, muscle
fatty tissue
|
growth hormone
|
Increases: glycogenolysis
lipolysis
|
Liver
fatty tissue
|
Cortisol
|
Increases: gluconeogenesis
glycogen synthesis
proteolysis
Reduces: glucose uptake by cells
|
Liver
Liver
Muscles
Muscle, fat
|
Stimulated insulin secretion, in addition to
hyperglycemia, glucagon and intestinal polypeptide hormones including
gastrointestinal hormone-dependent insulinotropic polypeptide, amino acids,
free fatty acids, stimulation of the vagus.
Complex metabolic effects of insulin, it includes
direct effects on lipid metabolism, proteins, and especially in connection with
diabetes - D-glucose. Insulin increases membrane transport of glucose and amino
acids K +, activates many intracellular enzymes. At the same time, the insulin
polypeptide molecule is not able to penetrate through the cell membrane, so
that all the effects of insulin are made through specific membrane receptors on
the cell surface. Insulin receptor complex, it consists of α- and β-subunits
linked by disulfide bridges.
High levels of insulin in the blood have anabolic
and low - catabolic effects on metabolism.
Insulin resistance may develop, acute resistance
associated with infections or inflammation. Resistance can be determined by the
appearance of circulating antibodies to insulin (IgG) and tissue insensitivity,
which is often observed in obesity. The affinity (affinity to insulin receptor)
and / or the number of receptors is dependent on a number of factors; This
sulfonylurea drugs, pH, cAMP, physical activity, and the nature of the food
composition, antibodies and other hormones.
Glucagon - polypeptide consisting of 29 amino
acids secreted by α-cells of the islets of the pancreas, secretion decreases
with increasing concentration of glucose in the blood. Basically its opposite
effects of insulin action. Glucagon stimulated glycogenolysis and
gluconeogenesis in the liver and promotes lipolysis and ketogenesis.
Epinephrine is synthesized in the adrenal medulla,
it stimulates hepatic glycogenolysis and gluconeogenesis, skeletal muscle -
glycogenolysis and lipolysis, enhances lipolysis in adipose tissue.
hyperproduction of adrenaline is observed at pheochromocytoma, while blood can
be transient hyperglycemia.
Glucocorticoids are produced by the adrenal
cortex, increase gluconeogenesis, inhibit glucose transport, inhibit glycolysis
and the pentose phosphate cycle reduces protein synthesis, potentiate the
action of glucagon, catecholamines, growth hormone. Excessive production
glucocorticoid hydrocortisone characterized Cushing syndrome - Cushing in which
hyperglycemia occurs due to excessive formation of glucose from the proteins
and other substrates.
Thyroid hormones increase the rate of glucose
utilization, accelerate its absorption in the gut activated insulinase increase
the basal metabolic rate, including glucose oxides summer. Thyroid hormone has
metabolic effects through thyroid stimulation.
STH has a metabolic effect, has hyperglycemic
action in adipose tissue - lipolytic effect. With an excess of growth hormone
in children education is developed gigantism, adult - acromegaly. High blood
glucose feature of this disease.
Adrenocorticotropic hormone directly and through
the stimulation causes the release of glucocorticoids pronounced hyperglycemic
effect.
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