Term
What is secreted from the following pancreatic cells:
1. A cell
2. B cell
3. D cell
4. F cell |
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Definition
1. Glucagon
2. Insulin
3. Somatostatin
4. Pancreatic Peptide |
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Term
| T/F: Insulin is a catabolic hormone. |
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Definition
| False. Insulin is an anabolic hormone. It causes increased glucose uptake and storage of glucose, fatty acids, and amino acids. |
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Term
| What is the role of C-peptide in insulin formation? |
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Definition
| To ensure that proper disulfide bonds are formed between the A and B peptides. |
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Term
How is insulin inactivated?
Where does this occur? |
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Definition
| Cleavage of the disulfide bonds in either the liver or kidney. |
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Term
GLUT-1
1. What is the tissue distribution?
2. Cellular location?
3. Function? |
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Definition
1. Ubiquitous
2. Plasma Membrane
3. Basal glucose transport |
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Term
GLUT-2
1. What is the tissue distribution?
2. Cellular location?
3. Function? |
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Definition
1. Pancreatic B-cells, epithelial cells in kidney, intestine, liver
2. Plasma Membrane
3. Part of glucose sensor in pancreatic islets; low affinity transporter
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Term
GLUT-4
1. What is the tissue distribution?
2. Cellular location?
3. Function? |
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Definition
1. Skeletal Muscle, Adipose Tissue
2. Intracellular Vesicles
3. Mediates insulin-regulated glucose transport |
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Term
| How is insulin stored in the liver? |
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Definition
| In secretory granules along with C-peptide, and little proinsulin. |
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Term
| What is the most potent stimulator of insulin secretion? |
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Definition
| Glucose. B cells are activated when the cellular glucose concentration is high. This occurs when GLUT-2 transporters bring glucose into the pancreas. |
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Term
| How is insulin release biphasic? |
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Definition
First Release: Rapid, transient released of stored insulin
Second Release: Slow and Progressive. Requires insulin synthesis. |
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Term
| What is Priming, with regard to insulin? |
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Definition
| Brief exposure to elevated glucose levels enhances B cell responsiveness to later glucose increases. |
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Term
| What is Potentiation, with regard to insulin? |
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Definition
| The fact that certain agents, combined with glucose, increase the release of insulin. Oral glucose more effectively releases insulin over IV glucose because the potentiation with GIP. |
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Term
What are major stimulators of Insulin?
Inhibitors? |
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Definition
Glucose, Amino Acids, GIP, cAMP, Acetylcholine
Insulin, Somatostatin |
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Term
| T/F: The amount of insulin released reflects the ratio of stimulatory to inhibitory mediators. |
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Definition
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Term
| T/F: The insulin receptor is a dimer with alpha and beta subunits linked by disulfide bonds. |
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Definition
| False. It is a tetramer with 2 alpha and 2 beta subunits with disulfide linkages. |
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Term
| What is the response of the receptors to sustained insulin levels? |
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Definition
| It causes the down-regulation of the insulin receptors through increased degredation. |
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Term
1. What is the response of insulin within seconds?
2. Minutes?
3. Hours? |
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Definition
1. Increased glucose transport into insulin sensitive cells
2. Protein synthesis increases and protein degredation decreases
3. Increased synthesis of messenger RNA or anabolic enzymes |
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Term
| At what level must plasma glucose be maintained for adequate brain function? |
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Definition
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Term
| What is the counter-regulatory hormone to insulin? |
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Definition
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Term
| Where does Glucagon have greatest effect? |
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Definition
| In the liver; it has minimal effects on adipose tissue or muscle |
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Term
| What stimulates glucagon release? |
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Definition
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Term
| How does GABA from B cells affect glucagon secretion? |
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Definition
| GABA binds with receptors on the A cells and prevents glucagon release. |
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Term
1. What are the major stimulators of glucagon secretion?
2. Inhibitors? |
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Definition
1. Amino Acids, CCK, Gastrin, Exercise, Stress
2. Glucose, Somatostatin, Secretin, Insulin |
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Term
| What inhibits insulin and glucagon secretion? |
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Definition
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Term
| What is Pancreatic Peptide? |
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Definition
| An inhibitor of exocrine pancreas secretion. |
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Term
| Why is accelerated lipolysis and ketogenesis not observed in NIDDM as in IDDM? |
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Definition
| Because insulin is still present to control glucagon secretion, even though it is not effective in aiding in glucose transport in tissues. |
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Term
What treatments are given for IDDM?
NIDDM? |
|
Definition
Insulin
Diet and exercise, sulfonylurea drugs, eventually insulin |
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