Exam 5: The Endocrine Pancreas and Carbohydrate Metabolism Flashcards

1
Q

How is GLUT4 regulated?

A

Insulin

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2
Q

Where is a GLUT4 transporter not located?

A

Brain

Liver

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3
Q

How does insulin circulate?

A

Mostly unbound

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4
Q

What are the functions of insulin?

A

Anabolic
Decrease blood glucose
Facilitates tissue uptake of glucose, amino acids, fatty acids, K, Mg, and P
Stimulates glycogen synthesis, lipogenesis, protein synthesis and storage
Inhibits glycogenolysis, lipolysis, and protein catabolism

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5
Q

What does insulin receptor binding do?

A

Activates some intracellular enzymes and inactivates others

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6
Q

How quickly does the 1st insulin receptor binding result?

A

Within seconds

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7
Q

What happens after the 1st insulin receptor binding?

A

80% of body’s cells increase glucose uptake (muscle, adipose, not most neurons)
Immediate phosphorylation of glucose

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8
Q

Where is insulin not required the most for glucose transport?

A

Neurons

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9
Q

What are additional insulin binding effects?

A

Increase cell membrane permeability to amino acids, K, and P
Intracellular flow, so it will decrease blood concentration
Slower insulin effect, 10-15 min, which will increase or decrease activity level of many intracellular enymes

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10
Q

What does muscle do in the presence of insulin?

A

Absorbs glucose for immediate energy

Synthesizes glycogen for use later

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11
Q

What does the liver do in the presence of insulin?

A

Stimulates glycogenesis

Inhibits glycogenolysis

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12
Q

What does insulin on liver CHOs promote?

A

Glucose storage in the form of glycogen

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13
Q

What happens when insulin enhances the liver’s glucose uptake and retention?

A

Increase activity of glucokinase

Decrease activity of phosphatase

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14
Q

What happens when insulin activates glycogen synthesis enzymes?

A

Increase glycogen synthase

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15
Q

What happens when insulin inhibits the breakdown of glycogen?

A

Decrease activity of liver phosphorylase

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16
Q

What happens to the liver in the absence of insulin?

A

Releases glucose into the circulating blood

17
Q

What happens with the promotion of fat synthesis and storage by insulin?

A

Carbohydrate excess (promotion of fatty acid synthesis in hepatocytes)
Promotes FA transport to and storage in adipose tissue
Inhibits lipolysis

18
Q

What does lipoprotien lipase (activated by insulin and FA) allow?

A

Storage of TG in adipose tissue

19
Q

What occurs with lipid and insulin deficiency?

A

Lipolysis

Ketone formation in liver

20
Q

What does insulin promote for protein?

A

Protein synthesis and storage

21
Q

What does the promotion of protein synthesis and storage by insulin do?

A

Stimulates transport of amino acids into cells, including muscle
Inhibits protein catabolism
Decrease hepatic gluconeogenesis

22
Q

What does the stimulation of transport of amino acids do?

A

Increase translation of mRNA

23
Q

What is the primary regulator of insulin release?

A

Blood glucose

24
Q

How does glucose enter β cells?

25
What is glucose proportional to?
Blood glucose concentration
26
What does the rate of glucose entry control?
Excytosis of insulin vesicles
27
What does high BG do to insulin secretion?
Increases it
28
What does low BG do to insulin secretion?
Decreases it
29
What are the functions of glucagon?
``` Anti-insulin/diabetogenic Rapid acting Hepatic glycogenolysis Hepatic gluconeogenesis Lipolysis ```
30
What does decreased glucose do to glucagon secretion?
Increases it
31
What does increased glucose do to glucagon secretion?
Decreases it
32
What do amino acids do in glucagon regulation?
Stimulate glucagon secretion