Molecular Basis of Type 2 Diabetes

Question 1

T/F insulin increases the volume of distribution of galactose

Answer 1

T –> increasing Vd by distributing glucose to muscle reduces plasma steady state glucose concentration

Question 2

_____ is the insulin regulated rate limiting step to glucose metabolism

Answer 2

transport across plasma membrane

Question 3

Translocation hypothesis

Answer 3

insulin upregulates # of glucose (glut4 - muscle/fat) transporters on cell membrane

Question 4

What signals insertion of glut4 receptors into cell membrane?

Answer 4

insulin or muscle contraction

Question 5

Implications of translocation hypothesis in T2D

Answer 5

glucose transport is insensitive to insulin but sensitive to contraction in T2D –> exercise can be effective in inducing glucose uptake

Question 6

the inability of insulin to reduce hepatic output and stimulate glucose uptake in cells.

Answer 6

insulin resistance

Question 7

If you have a high blood sugar during fasting where is the defect?

Answer 7

in hepatic glucose output (because muscle uptake at fasting/in absence of insulin is close to 0)

Question 8

If you have high blood sugar after eating, where is the defect?

Answer 8

Either resistance at the membranes of muscle cells preventing glucose uptake OR resistance at the liver preventing shutdown of glucose output

Question 9

Insulin resistance on fat

Answer 9

rate of FA release into bloodstream increases

Question 10

Impact of increased FA

Answer 10

liver produces more triglycerides

Question 11

Why are fatty acids transported as VLDL and then broken down at the target site instead of just being transported as is?

Answer 11

In times of starvation, the volume of fatty acids being transported would lower the blood pH –> conversion increases carrying capacity of blood

Question 12

Insulin resistance syndromes involve a ____ impairment in insulin action

Answer 12

selective –> e.g. liver should not produce triglycerides if insulin resistant –> possible that liver is insulin resistant in context of glucose but not in context of lipids

Question 13

T/F Central obesity is a risk factor for T2D

Answer 13

T –> more of a factor than gynoid obesity

Question 14

T/F BMI is a good indicator of adiposity

Answer 14

F –> people have different lean/fat ratios

Question 15

How might lipids relate to insulin resistance

Answer 15

1. if have lots of fat, excess spills into blood as ffa –> goes to muscles and tissues and stimulates insulin resistance
2. in crease in fat mass –> activation of immune system –> insulin resistance