Endocrine at Home Flashcards
Diabetes (def)
A group of disorders of (1), which is a syndrome characterized by (2) and (3)
(1) glucose homeostasis
(2) chronic hyperglycemia
(3) other disturbances in carbohydrate and fat metabolism
Three interrelated processes of glucose regulation
(1) Gluconeogenesis
(2) Glycgen synethesis, glycogenolysis
(3) Insulin mediated regulation
Gluconegenesis
- What is it
- Where
- Glucose production
- In the liver (and sometimes kidneys)
Glycogen synthesis / glycogenolysis
- What is it
- Where
- Glucose storage
- Skeletal muscle, liver
Insulin-mediated glucose regulation
- What is it
- Where
- Glucose uptake
- Peripheral tissue (esp skeletal muscle, fat and liver)
What are the two stages of normal fluctuations in plasma glucose?
- Absorptive state
- Post-absorptive state
What is the body’s priority during the absorptive state?
To decrease plasma glucose (prevent marked elevation)
What 5 mechanisms does the body employ during the absorptive state?
- Decrease in gluconeogenesis
- Decreasse in genolysis
- Increase in tissue permeability to glucose (especially skeletal muscle mediated by insulin)
- Increase in glycogen synthesis (glucose storage)
- Limit use of fat as primary energy source / increase lipogenesis (fat storage)
What is the body’s priority during the post-absorptive state?
To increase / maintain plasma glucose (prevent marked drop)
What 4 mechanisms does the body employ during the post-absorptive state?
- Glycogenolysis
- Gluconeogenesis
- Limit access to glucose to only those tissues that absolutely need it like the CNS (insulin level drops)
- Use of fat as primary energy source (lipolysis)
Why does the body use fat as the primary energy source during the post-absorptive state?
To conserve glucose for use by CNS and other tissue that can’t use fat as an energy source
Three ways glucose gets into and out of the cell:
1) Facilitated diffusion
2) Requires a protein transporter (glucose transporters
3) Requires a concentration gradient
Two glucose transporters (of the 4)
- Glut-1 Transporters
- Glut-4 tranporters
Four characteristics of Glut-1 Transporters
- Allow glucose to enter the cell
- Constitutively expressed (on all cells, but in low density)
- Responsible for low levels of basal glucose uptake required to sustain energy generation by all cells
When is expression of Glut-1 Transporters Increased?
Expression is increased with prolonged fasting and decreased with persistent exposure to excessive glucose
Where are glut-4 transporters expressed? (3)
• Expressed in cardiac, sk muscle, adipose, liver tissue
What are Glut 4 Transporters responsible for?
- Mechanism
• Responsible for insulin stimulated uptake of glucose
Mechanism of Glut-4 Transporters
• PI-3K signaling pathway enables GT4 receptor to get inserted → glucose uptake
Events stimulated by the PI-3K pathway
- Enables GT4 Receptor to get inserted → Glucose uptake
- Proliferation
- Synthesis of lipids, protein and glycogen
- All of the enzymes to convert glucose into triglycerides
- All of the enzymes needed to stimulate glycogen
What event does MAPK help the PI-3K pathway with?
Proliferation and cell growth
Along with PI-3K and MAPK, what else acts as a growth factor?
INSULIN
What are the exocrine components of the pancreas? (1)
Pancreatic ducts
What are the endocrine components of the pancreas, and what does each produce? (2)
- Alpha cells (glucagon)
- Beta cells (insulin)
Characteristics of Glucagon (5)
o Produced by alpha cells o Hormone of the post-absorptive state o Enzymes necessary for glycolysis o Enzymes that inhibit lipogenesis o Causes retraction of gluten 4 inhibitors
