Diabetes Mellitus Flashcards Preview

Biochemistry Post Midterm > Diabetes Mellitus > Flashcards

Flashcards in Diabetes Mellitus Deck (28):
1

what is DM?

a group of disorders characterized by the presence of HYPERGLYCEMIA that results from defects in SECRETION OF INSULIN OR ACTION OF INSULIN OR BOTH

2

what can DM result in?

blindness
renal failure
CVD
stroke...

3

what are the types of DM?

type I - insulin dependent
type II - non insulin dependent
gestational diabetes
secondary diabetes

4

what is type I DM due to?

autoimmune destruction of beta cells of islet of pancreas - marked reduction in insulin secretion

5

what is type II DM due to?

obesity (syndrome x/metabolic syndrome/insulin resistance syndrome)

target tissues do NOT response to circulating insulin - insulin resistant! and there is a decrease in insulin secretion over time = beta cell fatigue! (so insulin levels can be high, normal, low depending on stage of the disease)

6

what is the most common cause of insulin resistance in obesity?

-decreased number of insulin receptors
-postreceptor failure to activate tyrosine kinase

7

what may insulin resistance in obese people also be due to...?

-reduced adiponectin
-increase leptin (leptin resistance)
-increase free FA
-omentin
-reduced glucagon like peptide (GLP-1)

8

what is omen tin?

protein expressed and secreted from visceral but not subcutaneous adipose tissue

plasma levels of omen tin-1 are higher in people with higher WHR

9

what is GLP-1?

an incretin that increases insulin secretion

10

what are the presenting features of DM?

-polydipsia
-polyphagia
-dehydration
-decreased immunity
-polyuria

11

what is the classical triad of DM? more common with type I DM

polyuria
polydipsia
polyphagia

12

why may weight loss be observed in patients with type 1?

accelerated lipolysis and muscle proteolysis

13

what type of metabolism does DM affect?

protein,carb,fat

14

why is there hyperglycemia with DM?

increase gluconeogenesis in liver
+PEPCK
+pyruvate carboxylase
+ F 1,6 BP
+ G-6-P

decreased number of GLUT 4 in peripheral tissues

both because of decreased number of insulin receptors/post receptor defects

also... decreased secretion of insulin from pancreas

15

what is inhibited with low insulin and high glucagon?

glycolysis
glycogenesis

16

where is glucose completely reabsorbed?

renal tubule

17

why is there polyuria in DM?

with hyperglycemia - lots of glucose is filtered that may exceed the capacity of the tubule so now glucose is osmotically active and drags water along with it - they both leave in urine!

18

what are the acute complications of DM?

ketoacidosis - type I
hyperosmolar non-ketotic coma - type II
hypoglycemia in DM on treatment

19

what are the chronic complications of DM?

microvascular
macrovascular

20

what are microsvascular complication of DM?

-neuropathy
-nephropathy
-retinophathy

occurs in tissues that do not require insulin for glucose entry - retina, nervous tissue, lens

21

how can hyperglycemia result in tissue damage?

sorbitol formation - vision changes

22

what contributes to nephropathy?

non-enzymatic glycation of proteins in the BM of kidney

AGEs (advanced glycation end products)

23

what is the earliest sign of renal involvement in a diabetic?

increased loss of albumin in urine (microalbuminuria)

24

what are macrovascular complications of DM?

atherosclerotic changes
hypertriacylglyceridemia - due to decreased action of LPL
AGEs - glycation of LDL

25

what are lab tests that diagnose DM?

fasting BG > 126
random BG > 200
OGTT

26

define pre-diabetics?

fasting BG of 100-125 - IFG

or

2 hour post oral glucose TT GL 140-200 --IGT

comonly associated with insulin resistance / obesity

advice dietary mod. + exercise

27

what is sulonylurea?

increases insulin secretion from pancreas

28

what is metformin?

decreases glucose output of liver, increases glucose utilization by muscle - improves insulin resistance