B2.046 Prework 1 Overview of Hyperglycemia in Type 1 Diabetes

Question 1

what is glucosuria?

Answer 1

sweet taste of urine

glucose being excreted in urine

Question 2

what is SGLT2 and what is its function?

Answer 2

actively transports glucose from lumen into renal tubule cells by coupling with Na+ transport

Question 3

what is the renal blood glucose threshold?

Answer 3

160-180 mg/dl

Question 4

what are some examples of diabetic macro and microvascular complications?

Answer 4

atherosclerosis
nephropathy
retinopathy

Question 5

distinguish between glycation and glycosylation

Answer 5

glycation- irreversible non enzymatic protein modifications

glycosylation- reversible, enzymatic protein modifications

Question 6

what are 4 negative effects of chronic hyperglycemia

Answer 6

glycation
glycosylation
altered cellular redox potentials
oxidative stress and inflammation

Question 7

what does Hb1Ac level exhibit?

Answer 7

the amount of Hb in the glycated state

more= more chronic hyperglycemia over last 6-8 weeks

Question 8

how is glucose usually structured and what structure is susceptible to glycation?

Answer 8

usually in alpha and beta rings

fleetingly in a chain; in this form it can spontaneously glycate Hb

Question 9

what is the primary hormonal basis for hyperglycemia in type 1 DM?

Answer 9

insulin is absent

glucagon, catechloamines, growth hormone, and glucocorticoids are present (counter regulatory hormones)

Question 10

what is required for transport of glucose into skeletal muscle and adipose?

Answer 10

GLUT4

stimulated by insulin

Question 11

what processes require insulin?

Answer 11

synthesis of glycogen by the liver and muscle
complete oxidation of glucose to CO2 by the heart, liver, and muscle
synthesis of fatty acids from glucose in the liver

Question 12

what processes are negatively controlled by insulin?

Answer 12

glucose synthesis by the liver
lipolysis in the adipose
proteolysis in the muscle
opposition of counter regulatory hormones

Question 13

glucokinase

Answer 13

stimulated by insulin in the liver

Question 14

glycogen synthase

Answer 14

dephosphorylated/activated by insulin

phosphorylated/deactivated by glucagon

Question 15

glycogen phosphorylase

Answer 15

phosphorylated/activated by glucagon

dephosphorylated/inactivated by insulin

Question 16

what is anaplerosis?

Answer 16

net synthesis of citric acid cycle intermediates

Question 17

what enzyme catalyzes anaplerosis?

Answer 17

pyruvate carboxylase

stimulated by high acetyl CoA levels and glucagon

Question 18

what are important enzymes in gluconeogenesis?

Answer 18

pyruvate carboxylase
PEPCK
fructose 1,6 bisphosphatase
glucose 6-phosphatase

Question 19

what are the steps of complete oxidation of glucose that are not functional without insulin?

Answer 19

glucose uptake
glycolysis
pyruvate dehydrogenase complex activation
citric acid cycle

Question 20

what primary enzymes are required for synthesis of fatty acids by the liver?

Answer 20

glucokinase
pyruvate dehydrogenase complex
acetyl coA carboxylase
fatty acid synthase

Question 21

how is acetyl coA carboxylase regulated?

Answer 21

down regulated and inhibited by phosphorylation when glucagon is released

Question 22

what is lipolysis and what enzyme catalyzes it?

Answer 22

triacylglycerol hydrolysis: TAG + 3 H2O yields 3 FFAs + glycerol
catalyzed by hormone sensitive lipase (HSL)

Question 23

what is responsible for muscle wasting in type 1 diabetes?

Answer 23

proteolytic mechanisms