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Flashcards in Metabolic Homeostatis Deck (33)
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1

What occurs with starvation?

-Proinflammatory cytokines
-Activation of HPA axis
-Dysregulation of growth hormone and IGF-I

2

What is the initial energy source for the brain?

Glucose.

80% from fat stores, release of FFAs, breakdown of liver glycogen, breakdown of proteins

3

What is the energy for the brain in a prolonged fast?

Ketone bodies used as energy source for brain with reduced reliance on glucose as fuel source

4

What is syndrome X?

It is a metabolic syndrome often combined with obesity and diabetes.

5

What are the four factors of syndrome X?

-Visceral Obesity
-Insulin Resistance
-Dyslipidemia – TGs > 150 mg/dl, HDL
-Hypertension

6

What is the primary hormone produced by adipose tissue?

Leptin

7

What is the function of Sterol regulatory binding protein 1C (SREBP-1C)?

Promotes TAG synthesis
Activated by lipids and insulin
Increases glucokinase “trapping” glucose inside cells.

8

What is the function of PPARgamma?

Nuclear steroid hormone receptor
Regulates TG storage and adipocyte differentiation

9

What is the function of PPARgamma agonists?

PPARγ agonists used to treat insulin resistance and Type 2 diabetes mellitus

10

What is the side effect of PPARgamma agonists?

Weight gain

11

What is the relationship between leptin and total fat?

Direct

12

What is insulin resistance?

Insulin does not efficiently transport glucose into cells -> due to constant high glucose levels and high insulin levels

13

What can beta cell exhaustion cause in diabetes patients?

Conversion from Type II to Type I

14

What is the main diagnosis factor for diabetes type II?

Elevated HbA1C - shows the glycosylation of RBCs which is over a longer period of time

15

What are the main symptoms of diabetes mellitus type II?

Polyphagia
Polyuria
Polydipsia

16

What is the mechanism of sulfonylureas in treating DM Type II?

Close ATP-dependent K+ channels in beta cells causing insulin release

17

What is the function of biguanides like metformin in treating DM Type II?

Inhibits hepatic gluconeogenesis

Increases insulin receptor activity making cells more sensitive to insulin, increased glucose uptake

18

What is the cause of DM Type I?

Destruction of pancreatic beta cells – causes insulin dependence

19

What is found in untreated DM Type I?

Ketoacidosis

20

How does diabetic ketoacidosis occur?

Decreased insulin ->
Increased counter regulatory hormones ->
Increased FFA release – hepatic precursor for ketone acids ->
Ketone metabolism ->
Increases blood [H+] ->
Prolonged increased acidity will lead to ketoacidosis and then coma

21

Does ketogenesis occur in absolute insulin deficiency, like Type I DM?

Yes

22

Does ketogenesis occur in relative insulin deficiency, like Type II DM?

No

23

Describe insulin and GH function in the fed state.

The presence of insulin with a mixed meal will lead to GH release which will stimulate IGF-I which will increase glucose uptake in muscle and inhibits proteolysis.

GH opposes lipgenesis of insulin

24

Describe insulin and GH function in the starvation state.

No insulin with low glucose and glucagon is stimulated as insulin is not there to inhibit it. GH will increase due to AAs from increased proteolysis.

No IGF-I with no insulin so there is no negative feedback on GH.

25

Describe insulin and GH function in DM Type I.

No insulin but there is HIGH glucose since the patient is eating. Glucagon is stimulated without inhibition though with no insulin.

GH will be increased with increased proteolysis with no negative feedback due to no IGF-I.

26

Describe insulin and GH function in DM Type II.

Low insulin or insulin is not receipted.

HIGH glucose with glucagon stimulated but it is inhibited since insulin is present. Presence of insulin also inhibits ketogenesis.

27

What are the risk factors for Type II DM?

Genetic predisposition

Impaired beta cell proliferation during childhood

Increased propensity for insulin resistance
-High caloric diet
-Lack of physical activity

28

When does islet cell development begin and end?

Islet neogenesis occurs during embryonic development and beta cell replication continues during childhood/adolescence but is stable in adults

29

What gene is important for both islet neogenesis and beta cell proliferation?

PDX-1

30

What gene targets regulate beta cell proliferation?

TCF72

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