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1QQ# 4 for 10:30
1. Which cell type(s) have Glut-4 transporters?a) liver b) skeletal muscle c) adipose d) neurons
2. True or False: Excess amino acids are stored as glycogen in hepatocytes.
3. Which cell type(s) have insulin receptors?a) liver b) skeletal muscle c) adipose d) neurons
1QQ# 4 for 11:30
1. Which cell type(s) lack Glut-4 transporters?a) liver b) skeletal muscle c) adipose d) neurons
2. True or False: Excess amino acids are stored as triglycerides in adipocytes.
3. Which cell type(s) have insulin receptors?a) liver b) skeletal muscle c) adipose d) neurons
Fig. 16.01A
bsor
ptiv
e P
hase
Lipoprotein Lipase
Once inside, glucose is converted to something else, thereby maintaining a concentration gradientfor facilitated diffusion ofglucose into cells.
=“sinks”Entry requiresGlut-4 transporters
?
The Integrator integrates multiple inputs
Glucose uptake, Storage, Lipogenesis
WHY? FF
Thinking about food, aroma,Factors that influence Insulin Secretion
and other Incretins
Fig. 16.02
Post-absorptive phase
Glucose SparingSpecial case:
Muscle wasting of starvation
Note: Nervous tissuecan use glucose and ketones
Special term:Glycogenolysis &Gluconeogenesis
Kidneys can convert amino acids to glucose!
The Issues
• How do cells “know” which fuel to “burn?”• How do cells “know” when to synthesize
glycogen and lipids and when to break down glycogen and lipids?
• What is responsible for the transitions from the absorptive and post-absorptive states?
Another hormone that regulates plasma glucose concentration
Glucagon prevails during post-absorptive phase
Transition from absorptive to post-absorptive phase?
Glucose-counterregulatory controls
(oppose effects of insulin)
Glucagon (target = hepatocytes)
Epinephrine (liver, adipocytes, skeletal muscle)Cortisol (permissive effect for liver, adipocytes, skeletal muscle)Growth hormone (permissive effect for liver, adipocytes, skeletal muscle)
Fig. 16.02
Post-absorptive phase
Glucose SparingSpecial case:
Muscle wasting of starvation
Note: Nervous tissuecan use glucose and ketones
Special term:Glycogenolysis &Gluconeogenesis
Kidneys can convert amino acids to glucose!
Insulin Receptor
Adrenergic Receptor
Cortisol Receptor
Glucagon Receptor
Fig. 16.10Don’t fret about receptors, afferent pathway, and integrator for this feedback loop.
Adrenergic receptor
A Case Study of Glucose Homeostasis A 35 year old male presented with the following complaints: frequent severe headaches upon awakening at 4:30 am, blurred vision, and fatigue due to excessive stress at work. The patient complained of routine 16 hr workdays followed by a midnight snack of breakfast cereal.
An OGTT was ordered and provided the following results: During the second hour of the OGTT, the patient exhibited anxiety, paleness, hunger, tremulousness, and cold sweat. No additional tests were ordered.
The patient was instructed to replace the midnight snack of cereal with a protein-rich snack.
Oral Glucose Tolerance Test
• Overnight fast, no beverages other than water
• Fasting blood sample• Ingest 75 grams glucose• Blood samples every 0.5
hours for 3-5 hours• Plot plasma glucose
concentration over time• Compare curves Sugar content
of Red Bull?