The in vivo regulation of pulsatile insulin secretion

N Pørksen1

  • 1Medical Department of Endocrinology and Metabolism, Aarhus University Hospital, Noerrebrogade, 8000 Aarhus C, Denmark. porksen@dadlnet.dk

Diabetologia
|February 15, 2002
PubMed

The presence of oscillations in peripheral insulin concentrations has sparked a number of studies evaluating the impact of the insulin release pattern on the action of insulin on target organs. These have convincingly shown that equal amounts of insulin presented to target organs have improved action when delivered in a pulsatile manner. In addition, impaired (not absent) pulsatility of insulin secretion has been demonstrated in Type II (non-insulin-dependent) diabetes mellitus, suggesting a possible mechanism to explain impaired insulin action in Type II diabetes. Whereas the regulation of overall insulin secretion has been described in detail, the mechanisms by which this regulation affects the pulsatile insulin secretory pattern, and the relative and absolute contribution of changes in the characteristics of pulsatile insulin release have not been reviewed previously. This review will focus on the importance of the secretory bursts to overall insulin release, and on how insulin secretion is adjusted by changes in these secretory bursts. Detection and quantification of secretory bursts depend on methods, and the methodology involved in studies dealing with pulsatile insulin secretion is described. Finally, data suggest that impaired pulsatile insulin secretion is an early marker for beta-cell dysfunction in Type II diabetes, and the role of early detection of impaired pulsatility to predict diabetes or to examine mechanisms to cause beta-cell dysfunction is mentioned.

Related Concept Videos

Insulin Secretory Vesicles01:05

Insulin Secretory Vesicles

Insulin secretory vesicles release insulin to stimulate blood glucose uptake and regulate carbohydrate metabolism. When the blood glucose levels increase, glucose enters the pancreatic β-islet cells through glucose transporters. Once inside, glucose is metabolized through glycolysis, the citric acid cycle, and the electron transport chain, producing ATP. This increase in ATP concentration closes ATP-sensitive potassium channels, leading to depolarization of the membrane and the opening of...
Hormones Regulating Blood Glucose01:16

Hormones Regulating Blood Glucose

Insulin is released by beta cells of the pancreas when blood glucose levels are high. It facilitates glucose absorption and utilization in insulin-dependent cells with insulin receptors on their plasma membranes. Insulin promotes glucose uptake by increasing the number of glucose transport proteins in the cell membrane, allowing glucose to enter the cell. As a result, glucose utilization and ATP production are enhanced.
In addition to accelerating glucose uptake and utilization, insulin has...
Glucose Homeostasis: Regulation of Blood Glucose01:02

Glucose Homeostasis: Regulation of Blood Glucose

Carbohydrates consumed through foods are converted into glucose, a crucial energy source for the body. In the prandial state, high blood glucose levels stimulate the secretion of insulin from the pancreas. Insulin inhibits hepatic glucose production and stimulates glucose uptake and metabolism by muscle and adipose tissue. The excess glucose is converted into glycogen and stored in the liver and muscles.
During fasting, when blood glucose levels are low, the pancreas secretes glucagon. it...
Glucose Homeostasis: Pancreatic Islets and Insulin Secretion01:27

Glucose Homeostasis: Pancreatic Islets and Insulin Secretion

The pancreatic islets comprising only 1%-2% of the volume are highly vascularized and innervated mini-organs. They contain five endocrine cell types, including β cells that secrete insulin, which is synthesized as a single polypeptide chain, preproinsulin, processed to proinsulin, and finally to insulin and C-peptide. This process is complex and regulated, involving the Golgi complex, the endoplasmic reticulum, and the secretory granules of the β cell.
Insulin and C-peptide are co-secreted in...
Insulin: Dosing Regimen and Adverse Effects01:16

Insulin: Dosing Regimen and Adverse Effects

Insulin-replacement therapy usually includes both long-acting insulin (basal) and short-acting insulin (to cater to postprandial needs). In a diverse group of type 1 diabetes patients, the average daily insulin dose is typically 0.5-0.7 units/kg body weight. However, obese patients and pubertal adolescents may need more due to insulin resistance.
The basal dose constitutes about 40%-50% of the total daily dose, with the rest as premeal insulin. The mealtime insulin dose should mirror...
Glucagon-like Receptor Agonists01:24

Glucagon-like Receptor Agonists

Incretins include glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), which stimulate insulin secretion post-meals. In type 2 diabetes, GIP's efficacy is reduced, making GLP-1 a viable drug target. GIP originates from preproGIP.
GLP-1, when administered in high doses intravenously, triggers insulin secretion, inhibits glucagon release, slows gastric emptying, reduces food intake, and restores normal insulin secretion. However, its rapid inactivation by the...