Effects of insulin Flashcards
Effects of insulin within cell

3 effects of insulin on the liver
- Increased glycogen synthesis 2. Increased glycolysis 3. Decreased gluconeogenesis
3 effects of insulin on fat
- Increased glucose transport 2. Increased lipogenesis 3. Decreased lipolysis
3 effects of insulin on skeletal muscle
- Increased glucose transport (= fat) 2. Increased glycogen synthesis (= liver) 3. Decreased gluconeogenesis
What receptors does the heart have
GLUT 1 & some GLUT 2
=> heart gets a low level of glucose all of time even in the absence of insulin
Effect of insulin on glycogen metabolism (in hepatocytes)
see folder

Insulin regulated metabolism in an adipocyte
see folder

Relationship between EC & IC glucose and insulin
Linear relationship (graph)

- What does insulin stimulate (5) 2. What does insulin inhibit (5)
Image

What is the structure of glucagon
Peptide hormone 29 AAs
What is glucagon produced by
Alpha cells -20%
What is the half life of glucagon
5-10 mins degraded by liver tissue
3 factors that increase glucagon secretion
- Blood glucose < 70 mg/dL 2. AAs (high protein, low CHO meal) 3. Stress - adrenaline via beta-adrenergic receptors on alpha cells
2 factors that decrease glucagon secretion
- Increase blood glucose 2. Insulin (feed-forward mechanism)
Target tissues of glucagon
Liver muscle adipose tissue
What is the mechanism of action of glucagon
Binds to Gs-coupled receptor, resulting in increased cAMP and increased PKA activity - also activated IP3 pathway => increase in Ca2+
Action of glucagon on the liver (3)
PRIMARY TARGET - increase blood glucose
- Increased glycolysis - Activates a phosphorylase - cleaves a 1-P off glycogen
- Inhibits glycogenesis - Inactivates glycogen synthase by phosphorylation
- Increased gluconeogenesis - Increases phosphoenolpyruvate carboxykinase
Action of glucagon on lipids
Increases lipolysis - activates lipases - breaking down of triglycerides
- inhibits acetyl CoA carboxylase - stops FFA from becoming acetyl CoA
Glucagon action on cells
see folder

Response to decreasing glucose levels
photo

Where was somatostatin first discovered and where is it found now
Hpothalamus - GHIH
Pancreas, intestinal tract, CNS
What does somatostatin do
Inhibits secretion of many other hormones: 1. GH 2. Insulin 3. Glucagon 4. Exocrine pancreatic secretions
What are the 2 forms of somatostatin
SS-14 & SS-28
Tissue-specific isoform of SS-14
Sole isoform from pancreas Major isoform in CNS





