topic 10 insulin resistance Flashcards
how many lessons?
Lesson1:glucose hemostasis
Lesson2:Insulin &insulin resistance
Lesson3:obesity and insulin dysregulation
interactions between different organs and tissue in glucose homeostasis
somatostatin is produced which 3 places?
pancreatic hormones
glucagon
amylin
insulin
somatostatin
ghrelin
where does ghrelin produced?
stomach and ?
full name of GIP?
Gastric inhibitory polypeptide (GIP)
full name for GLP-1?
glucagon‐like peptide‐1 (GLP‐1)
what are GIP and GLP-1 function?
stimulate insulin secretion from pancreatic β cells.
where are GIP and GLP-1 produced?
two primary incretin hormones secreted from the intestine on ingestion of glucose or nutrients
what is CCK?
cholecystokinin
where is CCK produced?
small intestine(SI)
what triggers the release of cholecystokinin?
When cells in the mucosal lining of your duodenum (called I-cells) detect the presence of proteins and fats to digest, they trigger cholecystokinin to release into circulation.
what’s the function of cholecystokinin?
- It stimulates your gallbladder to contract and release bile into your small intestine.(“Cholecystokinin” means to “move the gallbladder.”
- It stimulates your pancreas to release pancreatic enzymes. (This is what its other name, “pancreozymin,” means.)
- cholecystokinin suppresses gastric emptying so your stomach won’t deliver any more food until the first batch is done.
4.It also suppresses your appetite while you’re digesting, by making your stomach feel physically full and by activating vagal nerves in your stomach wall.
5.Finally, it triggers peristalsis, the muscle contractions that move food along through your intestines to continue the digestive process.
glycolysis?
糖酵解，释放能量
glycogenesis?
糖原生成,消耗能量
glycogenolysis?
糖原分解，释放能量
gluconeogenesis
糖异生，消耗能量
insulin, glucagon and energy related process?
insulin: glycolysis+, glycogenesis+, glycogenolysis-, gluconeogenesis-
glucagon: glycolysis-, glycogenesis-, glycogenolysis+, gluconeogenesis+
why insulin, glucagon have such a relationship with those energy related process?
insulin is produced when body met a high blood sugar level, so to decrease blood level and reserve energy
glucagon is produced when a low blood sugar level, to use any means to raise blood sugar level, verse vasa with insulin
what is GLUT?
glucose transporter
how is GLUT-4 translocation stimulated?
insulin and exercise
How Does IR(insulin residence) develop?
hyperglycemia
physical inactive
genetic factors
Oxidative Stress
Dyslipidemia
Adipocytokine induced IR
Inflammation
what is IR?
Insulin-dependent cells fail to respond properly to normal circulatory concentrations of insulin—-Higher levels of insulin required for normal response
where would IR effect human body?
skeletal muscle, adipocytes and liver tissue
which part of human body has most GLUT-4
Muscle & adipocytes account for ~ 60-70% of insulin-stimulated glucose uptake via GLUT4 receptors
How would IR effect skeletal muscle
IR impairs损害 glycogen synthesis & protein catabolism in skeletal muscle
How would IR effect adipocytes?
IR impairs lipoprotein lipase LPL activity in adipocytes leading to increase in FFA and inflammatory cytokines
how would IR effect liver
- IR impairs glucose output & fatty acid metabolism
- Increasing VLDL & triglycerides
liver insulin-stimulated glucose uptake?
Liver accounts for ~ 30% of insulin-stimulated glucose uptake
which glucose transporter is insulin dependent?
GLUT-4
how does oxidative stress lead to IR?
↓ insulin signal transduction
↑adipokine dys`regulation
IR degradation
Excess free radicals suppress GLUT4 localization by impairing insulin signaling cascade and reducing GLUT4 expression
what would cause oxidative stress?
Overnutrition increases cellular load of glucose & FFAs
why oxidative stress will cause insulin resistance
Peripheral & adipose tissue protect themselves from damaging effects of oxidative stress by producing insulin resistance to prevent penetration of glucose & FFA into cells
Peripheral fat vs Visceral fat
Visceral fat: fat besides organs
Peripheral fat : under skin subcutaneous fat)
what is CEPT
cholesterol ester transfer protein
what are the Most important adipose-derived
mediators
FFAs(free fatty acids) & adipokines
how is insulin resistance induced by adipocytokine?
what are adipokines?
Adipokines are a family of polypeptides synthesized by adipocytes that include over 100 different molecules: leptin and adiponectin are the most commonly ones.
what are the pro-inflammatory mediators
leptin, TNF-α, IL-6 & apelin
what could leptin do?
a hormone produced by fat cells. It plays a role in regulating appetite and metabolism. However, it can also have pro-inflammatory effects.
what would TNF-a(Tumor Necrosis Factor-a) do? (FYI)
TNF-α is a cytokine involved in systemic inflammation. It is produced by various cells of the immune system and plays a role in the body’s response to infection and inflammation.
what would IL-6 do?(FYI)
IL-6 is another cytokine that has pro-inflammatory properties. It is produced by various cells, including immune cells, and is involved in the regulation of the immune response.
what would apelin do?
Adipokines responsible for local inflammation in adipocytes but may also induce system inflammation after entering circulation
yes or no
yes
Adiponectin vs Adipokines
adiponectin 脂联素
adipokine(adipocytokine)脂肪因子
what would adiponectin do?
Adiponectin may ameliorate negative effects
* Positively associated with insulin sensitivity
* Downregulated in obesity(在肥胖的情况下，脂联素的水平往往会降低。)
GIP and GLP-1
促进胰岛素，但机制不同
