insulin

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.

• Hormonal Regulation of Metabolism

  • Insulin is produced by the beta cells of the pancreas, which are stimulated to release insulin as blood glucose levels rise (for example, after a meal is consumed).
  • As insulin binds to its target cell via insulin receptors and signal transduction, it triggers the cell to incorporate glucose transport proteins into its membrane.
  • It can be caused by low levels of insulin production by the beta cells of the pancreas, or by reduced sensitivity of tissue cells to insulin.
  • Oversecretion of insulin can cause hypoglycemia, low blood glucose levels.
  • In this way, insulin and glucagon work together to maintain homeostatic glucose levels .

• 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.

• Pancreas

  • As an endocrine gland, the pancreas produces several important hormones,such as insulin and glucagon, which are secreted into the bloodstream to regulate blood sugar levels, along with other activities throughout the body.
  • The pancreatic islets contain two primary cell types: alpha cells, which produce the hormone glucagon, and beta cells, which produce the hormone insulin.
  • When blood glucose levels rise, such as after a meal, beta cells release insulin to lower blood glucose levels by increasing the rate of glucose uptake in most body cells, and by increasing glycogen synthesis in skeletal muscles and the liver.
  • The alpha and beta cells produce glucagon and insulin, respectively.

• Large-Scale Fermentations

  • These recombinant products include numerous pharmaceuticals such as insulin and hepatitis B vaccine.
  • Insulin is used medically to treat individuals diagnosed with diabetes mellitus.
  • Specifically, individuals with type 1 diabetes are unable to produce insulin and those with type 2 diabetes often develop insulin resistance where the hormone is no longer effective.
  • The increase in individuals diagnosed with diabetes mellitus has resulted in an increase in demand for external insulin.
  • The mass production of insulin is performed by utilizing both recombinant DNA technology and fermentation processes.