insulin

(noun)

A polypeptide hormone that regulates carbohydrate metabolism.

Related Terms

  • ketoacidosis
  • diabetes mellitus
  • glucagon
  • glycogen
  • somatostatin
  • macrosomia
  • beta cells

Examples of insulin in the following topics:

  • Insulin Secretion and Regulation of Glucagon

    • Glucagon is a peptide hormone that works in conjunction with insulin to maintain a stable blood glucose level.
    • Insulin is produced by beta cells in the pancreas and acts to oppose the functions of glucagon.
    • When control of insulin levels fails, diabetes mellitus can result.
    • As a consequence, insulin is used medically to treat some forms of diabetes mellitus.
    • Patients with type 2 diabetes are often insulin resistant and, because of such resistance, they may suffer from a relative insulin deficiency.
  • Pancreatic Islet Disorders: Diabetes and Hyperinsulinism

    • Hyperinsulinism refers to an above-normal level of insulin in the blood of a person or animal.
    • This refers to an above-normal level of insulin in the blood of a person or animal.
    • Normal insulin secretion and blood levels are closely related to the level of glucose in the blood, so that a given level of insulin can be normal for one blood glucose level but low or high for another.
    • Hyperinsulinism can be associated with several types of medical problems, which can be roughly divided into two broad and largely non-overlapping categories: those tending toward reduced sensitivity to insulin and high blood glucose levels (hyperglycemia), and those tending toward excessive insulin secretion and low glucose levels (hypoglycemia).
    • The most common forms of hypoglycemia occur as a complication of treatment of diabetes mellitus with insulin or oral medications.
  • Metabolic Changes

    • Protein and carbohydrate metabolism are affected during pregnancy and maternal insulin resistance can lead to gestational diabetes.
    • Maternal insulin resistance can lead to gestational diabetes.
    • Gestational diabetes is caused when the insulin receptors do not function properly.
    • This is likely due to pregnancy related factors such as the presence of human placental lactogen that interferes with susceptible insulin receptors.
    • Insulin binds to its receptor (1) on the cell membrane which in turn starts many protein activation cascades (2).
  • Disease as Homeostatic Imbalance

    • Insulin transports glucose to the body's cells for use in cellular metabolic function.
    • Because this ultimately lowers blood glucose levels, insulin is secreted to prevent hyperglycemia (high blood sugar levels).
    • Negative feedback between insulin and glucagon levels controls blood sugar homeostasis.
    • People with type 1 diabetes do not produce insulin due to auto-immune destruction of the insulin producing cells, while people with type 2 diabetes have chronic high blood glucose levels that cause insulin resistance. 
    • Diabetes is normally treated with insulin injections, which replaces the missing negative feedback of normal insulin secretions.
  • Postabsorptive State

    • This is accomplished via increased glucose levels from glucagon and decreased glucose levels from insulin.
    • However, chronic insulin and glucagon deficiencies still remain victims of diabetes.
    • These findings do not distinguish the individual roles of insulin and of glucagon.
    • However, chronic insulin and glucagon deficiencies have been proven to cause hyperglycemia and, therefore, strongly suggest that insulin is the predominant factor of postabsorptive glucose levels.
    • The flactuations of glucose and insulin in human during the course of a day
  • Type 1 Diabetes Mellitus

    • Diabetes mellitus type 1 (Type 1 diabetes, T1DM, formerly insulin-dependent or juvenile diabetes) is a form of diabetes mellitus that results from autoimmune destruction of insulin-producing beta cells of the pancreas.
    • The subsequent lack of insulin leads to increased blood and urine glucose.
    • Eventually, type 1 diabetes is fatal unless treated with insulin.
    • Injection is the most common method of administering it; other methods are insulin pumps, and inhaled insulin.
    • Today, the most common insulins are biosynthetic products produced using genetic recombination techniques; formerly, cattle or pig insulins were used, and even sometimes insulin from fish.
  • Interactions of Hormones at Target Cells

    • These cells control blood glucose concentration by producing the antagonistic hormones insulin and glucagon.
    • Beta cells secrete insulin.
    • When the concentration of blood glucose rises, such as after eating, beta cells secrete insulin into the blood.
    • Insulin stimulates the liver and most other body cells to absorb glucose.
    • In response, glucose concentration decreases in the blood, and insulin secretion discontinues through negative feedback from the declining levels of glucose.
  • Types of Cells in the Pancreas

    • It is an endocrine gland that produces several important hormones, including insulin, glucagon, somatostatin, and pancreatic polypeptide.
    • Beta cells that produce insulin and amylin, and make up 65–80% of the total islet cells.
    • Insulin lowers blood glucose levels by stimulating cells to take up glucose out of the blood stream.
    • The right image is the same section stained by immunofluorescence against insulin, indicating beta cells.
  • Hormones of the Digestive System

    • For instance, more connections to metabolic control (largely the glucose-insulin system) have been uncovered in recent years.
    • Another function is to induce insulin secretion.
    • The pancreas releases the hormone insulin, which targets the hypothalamus and also aids in suppressing our appetite after we have just eaten and there is a rise in blood glucose levels.
  • Aging and the Endocrine System

    • Three hormone axes are affected by aging: growth hormone/insulin-like growth factor I, cortisol/dehydroepiandrosterone, and testoterone/estradiol.
    • Three of the most important hormone axes in the endocrine system that are affected by aging include growth hormone (GH)/insulin-like growth factor I (IGF-I), cortisol/dehydroepiandrosterone (DHEA), and testosterone/estradiol.
    • Evaluate the effects of the hormonal axes affected by aging [growth hormone (GH)/insulin-like growth factor I (IGF-I), cortisol/dehydroepiandrosterone (DHEA), and testosterone/estradiol]
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