Duan-EBM

Question 1

Describe some of the organs that are involved in glucose homeostasis.

Answer 1

liver–glucagon causes glycogenolysis & glucose release
muscle–insulin causes glycogen synthesis
kidney–insulin causes increased absorption of glucose from filtrate
all tissues–insulin causes glucose to go into cells.

Question 2

What is released from pancreatic beta cells?

Answer 2

insulin
C-peptide
amylin

Question 3

What is released from pancreatic alpha cells?

Answer 3

glucagon

Question 4

Proteolysis of proinsulin yields what?

Answer 4

insulin
C-peptide
4 basic AA

Question 5

Describe the structure of insulin.

Answer 5

A & B chains (2)

joined by disulfide bonds & 1 intrachain bond

Question 6

What is the biologically active form of insulin?

Answer 6

monomeric form

Question 7

What’s the deal with human insulin preparations?

Answer 7

recombinant protein by genetic engineering.

Question 8

What types of substances in food cause secretion of insulin?

Answer 8

glucose–really stimulates insulin
AA–like arginine & lysine
fatty acids, ketones

Question 9

What type of nervous system things affect insulin release?

Answer 9

vagus nerve–M receptors–increases insulin release.

sympathetic activation–alpha receptor–>inhibits insulin release. beta 2 receptor–>activates insulin secretion.

Question 10

What types of things will cause sympathetic nerve stimulation & regulation of insulin release?

Answer 10

exercise
hypoxia
hypothermia
trauma
burns

Question 11

What does glucagon do to insulin release?

Answer 11

glucagon stimulates insulin secretion

Question 12

What does insulin do to glucagon release?

Answer 12

insulin inhibits release of glucagon

Question 13

T/F Injectable glucose stimulates more insulin release than eating glucose.

Answer 13

False. Eating causes more insulin release.

Question 14

Describe how glucose transport into pancreatic beta cells leads to insulin release.

Answer 14

glucose transported into beta cell via GLUT2.
rate limiting step: phosphorylation of glucose via glucokinase.
Metabolism of glucose–>more ATP.
High ATP–>inhibition of ATP sensitive K+ channel. Membrane depolarization. Ca++ rushes in & you get fusion of insulin-containing secretory granules w/ plasma membrane & exocytosis of insulin.

Question 15

Aside from glucose rushing in, what other substances help raise cAMP & cause exocytosis of insulin-containing granules?

Answer 15

GLP-1
incretins
acetylcholine (NT)

Question 16

Describe how insulin is broken down?

Answer 16

mainly by the liver & kidney
insulin binds receptor on cell & forms a complex that is internalized.
Complex degraded via thiol metalloproteinase (hydrolyzes disulfide linkage b/w A & B chains).
Receptor recycled to plasma membrane.

Question 17

What are the 3 main targets of insulin?

Answer 17

liver
muscle
adipose

Question 18

What does insulin do to the liver?

Answer 18

decreases gluconeogenesis & glycogenolysis
increases glucose uptake & glycolysis
increases triglyceride synthesis
increases protein synthesis

Question 19

What does insulin do to muscles?

Answer 19

increases glucose uptake & glycolysis
increases glycogen synthesis
increases protein synthesis.

Question 20

What does insulin do to adipose tissue?

Answer 20

increases glucose uptake & glycolysis
decreases intracellular lipolysis
increases lipogenesis & lipoprotein lipase activity

Question 21

What does insulin do overall to liver, muscle, fat?

Answer 21

Insulin stimulates utilization and storage of glucose, amino acids, and fatty acids, while inhibits breakdown of glycogen, protein, and fat.

Question 22

What does insulin do to glucose transportation & metabolism?

Answer 22

increases translocation of GLUT transporters to cell membrane
increases glucokinase
stimulates glycogen synthase
inhibits glycogen phosphorylase

Question 23

What are the 2 types of Type I diabetes?

Answer 23

Type 1A: autoimmune

Type 1B: nonautoimmune, idiopathic

Question 24

What do beta blockers do to patients with diabetes?

Answer 24

can cause hypoglycemia by depleting catecholamines & their gluconeogenesis & glycogenolysis

Question 25

What’s the deal with salicylates?

Answer 25

lower blood glucose by increasing pancreatic sensitivity to glucose–promote insulin secretion in Type 2 diabetics & non-diabetics.

Question 26

What is the pathogenesis of Type 2 DM?

Answer 26

hyperglycemia
sometimes insulin secretory dysfunction
increased insulin resistance (muscle, fat, liver)
increased endogenous glucose production
deranged adipocyte bio
decreased incretin effect

Question 27

what are the symptoms of diabetes?

Answer 27

Polyuria (urinating frequently)
Polydipsia (very thirsty)
Continuous hunger
Weight loss
Other symptoms
Fatigue
Dry skin
Frequent infections

Complications:
Retinopathy
Feet ulceration
Nephropathy
Cardiomyopathy
Neuropathy
Loss of sensibility in inferior extremities (legs)

Question 28

What are some important lifestyle changes for diabetes?

Answer 28

increased physical activity (30 min walk/day)
good diet, lower in fat & carbs
weight loss
taking: insulin, oral hypoglycemics

Question 29

Diabetes management should be individualized for patients with a1c<____.

Answer 29

7%

Question 30

Preprandial glucose & postprandial glucose should be what for patients with diabetes?

Answer 30

preprandial: 70-130
postprandial: <180

Question 31

What should LDL & TG be maintained at for diabetic patients?

Answer 31

LDL<150