B2.046 Prework 1 Overview of Hyperglycemia in Type 1 Diabetes Flashcards
what is glucosuria?
sweet taste of urine
glucose being excreted in urine
what is SGLT2 and what is its function?
actively transports glucose from lumen into renal tubule cells by coupling with Na+ transport
what is the renal blood glucose threshold?
160-180 mg/dl
what are some examples of diabetic macro and microvascular complications?
atherosclerosis
nephropathy
retinopathy
distinguish between glycation and glycosylation
glycation- irreversible non enzymatic protein modifications
glycosylation- reversible, enzymatic protein modifications
what are 4 negative effects of chronic hyperglycemia
glycation
glycosylation
altered cellular redox potentials
oxidative stress and inflammation
what does Hb1Ac level exhibit?
the amount of Hb in the glycated state
more= more chronic hyperglycemia over last 6-8 weeks
how is glucose usually structured and what structure is susceptible to glycation?
usually in alpha and beta rings
fleetingly in a chain; in this form it can spontaneously glycate Hb
what is the primary hormonal basis for hyperglycemia in type 1 DM?
insulin is absent
glucagon, catechloamines, growth hormone, and glucocorticoids are present (counter regulatory hormones)
what is required for transport of glucose into skeletal muscle and adipose?
GLUT4
stimulated by insulin
what processes require insulin?
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
what processes are negatively controlled by insulin?
glucose synthesis by the liver
lipolysis in the adipose
proteolysis in the muscle
opposition of counter regulatory hormones
glucokinase
stimulated by insulin in the liver
glycogen synthase
dephosphorylated/activated by insulin
phosphorylated/deactivated by glucagon
glycogen phosphorylase
phosphorylated/activated by glucagon
dephosphorylated/inactivated by insulin
what is anaplerosis?
net synthesis of citric acid cycle intermediates
what enzyme catalyzes anaplerosis?
pyruvate carboxylase
stimulated by high acetyl CoA levels and glucagon
what are important enzymes in gluconeogenesis?
pyruvate carboxylase
PEPCK
fructose 1,6 bisphosphatase
glucose 6-phosphatase
what are the steps of complete oxidation of glucose that are not functional without insulin?
glucose uptake
glycolysis
pyruvate dehydrogenase complex activation
citric acid cycle
what primary enzymes are required for synthesis of fatty acids by the liver?
glucokinase
pyruvate dehydrogenase complex
acetyl coA carboxylase
fatty acid synthase
how is acetyl coA carboxylase regulated?
down regulated and inhibited by phosphorylation when glucagon is released
what is lipolysis and what enzyme catalyzes it?
triacylglycerol hydrolysis: TAG + 3 H2O yields 3 FFAs + glycerol
catalyzed by hormone sensitive lipase (HSL)
what is responsible for muscle wasting in type 1 diabetes?
proteolytic mechanisms
