1QQ# 4 for 10:30

1. 1QQ# 4 for 10:30 • Which cell type(s) have Glut-4 transporters?a) liver b) skeletal muscle c) adipose d) neurons • True or False: Excess amino acids are stored as glycogen in hepatocytes. • Which cell type(s) have insulin receptors?a) liver b) skeletal muscle c) adipose d) neurons

2. 1QQ# 4 for 11:30 • Which cell type(s) lack Glut-4 transporters?a) liver b) skeletal muscle c) adipose d) neurons • True or False: Excess amino acids are stored as triglycerides in adipocytes. • Which cell type(s) have insulin receptors?a) liver b) skeletal muscle c) adipose d) neurons

3. Fig. 16.01 Lipoprotein Lipase Absorptive Phase =“sinks” Entry requiresGlut-4 transporters Once inside, glucose is converted to something else, thereby maintaining a concentration gradientfor facilitated diffusion ofglucose into cells.

4. Stimulatory actions of insulin in green Inhibitory actions of insulin in dashed red

5. ? Thinking about food, aroma, Factors that influence Insulin Secretion and other Incretins FF WHY? Glucose uptake, Storage, Lipogenesis The Integrator integrates multiple inputs

6. Fig. 16.02 Glucose Sparing Special case: Muscle wasting of starvation Special term: Glycogenolysis &Gluconeogenesis Kidneys can convert amino acids to glucose! Post-absorptive phase Note: Nervous tissuecan use glucose and ketones

7. 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?

8. Another hormone that regulates plasma glucose concentration Glucagon prevails during post-absorptive phase Transition from absorptive to post-absorptive phase?

9. 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)

10. Fig. 16.02 Glucose Sparing Special case: Muscle wasting of starvation Insulin Receptor Adrenergic Receptor Cortisol Receptor Glucagon Receptor Special term: Glycogenolysis &Gluconeogenesis Kidneys can convert amino acids to glucose! Post-absorptive phase Note: Nervous tissuecan use glucose and ketones

11. Fig. 16.10 Don’t fret about receptors, afferent pathway, and integrator for this feedback loop. Adrenergic receptor

12. Who Cares?

13. 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.

14. 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?

15. 60 Hypoglycemia

16. Stress,Emergency (fight or flight) Effect on Alpha Cells Effect on Beta cells

17. The Answer to the Problem? • Rationale for substituting protein for carbohydrate midnight snack?