Related Experiment Video
Updated: Jul 3, 2026
09:31
Assessing Replication and Beta Cell Function in Adenovirally-transduced Isolated Rodent Islets
Published on: June 25, 2012
The neuropeptide pituitary adenylate cyclase-activating polypeptide and islet function
K Filipsson1, M Kvist-Reimer, B Ahrén
1Department of Medicine, Lund University, Lund, Sweden.
Diabetes
|August 28, 2001
Summary
Pituitary adenylate cyclase-activating polypeptide (PACAP) regulates insulin secretion in pancreatic islets. This neuropeptide is crucial for the body's glucose-dependent insulin response to feeding.
Area of Science:
- Endocrinology
- Neuroscience
- Molecular Biology
Background:
- Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide found throughout the nervous system.
- PACAP plays a role in pancreatic islets, potentially acting as a neurotransmitter.
Purpose of the Study:
- To review the current understanding of PACAP's actions within pancreatic islets.
- To elucidate the mechanisms by which PACAP influences insulin secretion and glucose regulation.
Main Methods:
- Literature review of existing animal studies and research on PACAP.
- Analysis of molecular mechanisms involving cAMP formation and calcium uptake.
Main Results:
- PACAP stimulates insulin secretion in a glucose-dependent manner.
- PACAP's effects are mediated by increased cAMP production and calcium influx.
- Evidence suggests PACAP is physiologically important in regulating insulin response to feeding.
Conclusions:
- PACAP is a key regulator of insulin secretion in pancreatic islets.
- Understanding PACAP's function is vital for comprehending glucose homeostasis and feeding responses.
Related Concept Videos
01:05Insulin 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...
01:09GPCRs Regulate Adenylyl Cylase Activity
Some GPCRs transmit signals through adenylyl cyclase (AC), a transmembrane enzyme. AC helps synthesize second messenger cyclic adenosine monophosphate (cAMP). AC catalyzes cyclization reaction and converts ATP to cAMP by releasing a pyrophosphate. The pyrophosphate is further hydrolyzed to phosphate by the enzyme pyrophosphatase, which drives cAMP synthesis to completion. However, cAMP is rapidly degraded to 5′ AMP by the enzymes phosphodiesterase (PDE), preventing overstimulation of cells.
Two...
Two...
01:25cAMP-dependent Protein Kinase Pathways
Cyclic Adenosine Monophosphate (cAMP) is an essential second messenger that activates protein kinase A (PKA) and regulates various biological processes. A single epinephrine molecule binds to GPCR and activates several heterotrimeric G proteins, each stimulating multiple adenylyl cyclase, amplifying the signal, and synthesizing large numbers of cAMP molecules. Small changes in cAMP concentration affect PKA activity. The binding of four cAMP molecules induces a conformational change in PKA,...
01:16Cells and Secretions of the Pancreas
The pancreas, a vital organ within the abdominal cavity, plays dual roles in the digestive and endocrine systems, collaborating with exocrine and endocrine cells to maintain optimal digestion and blood sugar levels.
Exocrine function is carried out by acinar cells, organized into clusters known as acini. These cells contribute to digestion by releasing substantial quantities of enzyme-rich, alkaline digestive juices.
Concurrently, the dispersed clusters of endocrine cells throughout the...
Exocrine function is carried out by acinar cells, organized into clusters known as acini. These cells contribute to digestion by releasing substantial quantities of enzyme-rich, alkaline digestive juices.
Concurrently, the dispersed clusters of endocrine cells throughout the...
01:27Glucose 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 and C-peptide are co-secreted in...
01:24Glucagon-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...
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...