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CASE FILES: BIOCHEMISTRY
A N SW E R S TO C A SE 22: T Y PE II D IA B E T E S
Summary:
50-year-old obese Hispanic female presents with polydipsia, polypha-
gia, and urinary frequency and elevated random blood sugar of 320 mg/dL.
Diagnosis: Type II diabetes.
Other organ systems involved: Cardiovascular, eye, peripheral nerves,
gastrointestinal, kidney.
Biochemical basis: Insulin resistance as a result of a postinsulin
receptor defect. The insulin levels are normal or increased as compared
with normal individuals; however, the insulin is not “recognized,” and
thus the glucose levels remain elevated.
C L IN IC A L C O R R E L A T IO N
Diabetes mellitus is characterized by elevated blood glucose levels. It is com-
posed of two types depending on the pathogenesis. Type I diabetes is charac-
terized by insulin deficiency and usually has its onset during childhood or
teenage years. This is also called
ketosis-prone
diabetes. Type II diabetes is
caused by insulin resistance and usually has elevated insulin levels, and it is
diagnosed in the adult years. Type II diabetes is far more common than type I
diabetes. Risk factors include obesity, family history, sedentary life style, and,
in women, hyperandrogenic states or anovulation.
Diabetes mellitus is now recognized as one of the most common and sig-
nificant diseases facing Americans. It is estimated that 1 of 4 children born
today will become diabetic in their lifetime because of obesity and inactivity.
Also, it has been noted that diabetes has a severe effect on blood vessels, par-
ticularly in the pathogenesis of atherosclerosis (blockage of arteries by lipids
and plaque), which can lead to myocardial infarction or stroke. Diabetes mel-
litus is treated as equivalent to a prior cardiovascular event in its risk for future
atherosclerotic disease. Diabetes is also associated with immunosuppression,
renal insufficiency, blindness, neuropathy, and other metabolic disorders.
A PPR O A C H TO IN S U L IN A N D G L U C O SE
O bjectives
1.
Understand the role of insulin on carbohydrate metabolism.
2.
Be aware of the role of glucagon on carbohydrate metabolism.
3.
Know about the processes of gluconeogenesis and glycogenolysis.
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