L35- Diabetes Flashcards
Which type of diabetes results from a loss of beta-cells in the pancreas, leading to a defect in the production of insulin?
Type I diabetes (also called insulin-dependent diabetes).
Which type of diabetes results from a defect in the response to insulin?
Type II diabetes (also called insulin-independent diabetes).
What is most common type of diabetes in the United States?
Type II diabetes constitutes approximately 90% of diabetes cases.
A diabetic patient presents to your clinic with ketoacidosis. Which type of diabetes do you suspect?
Type I diabetes mellitus.
A 50 year-old diabetic patient presents to your clinic with high blood levels of insulin. Which type of diabetes do you suspect?
Type II diabetes mellitus.
What is the normal value for fasting plasma glucose (in mg/dl)?
Values less than 100mg/dl.
A value of fasting plasma glucose greater than ___ mg/dl would be considered consistent with diabetes.
125 mg/dl.
What value of blood glucose would a diabetic patient have (in mg/dl) two hours after a glucose challenge?
A value greater than 200 mg/dl.
Which glycolytic enzyme found in pancreatic beta-cells is stimulated by a rise in blood glucose concentrations and is involved in the release of insulin?
Glucokinase.
Which membrane channels directly control the secretion of insulin from beta-pancreatic cells?
Ca++ channels.
Glucose stimulates a rise in intracellular ATP in beta-pancreatic cells. Which channels are directly affected by this rise in ATP and what is their function?
ATP-dependent K+ channels. Binding of ATP to these channels causes the cell to depolarize. This triggers the opening of voltage-dependent Ca++ channels that in turn stimulate insulin secretion.
Which group of drugs act at K+ channel inhibitors and can therefore be used to enhance insulin secretion?
Sulfonylureas.
True or False. Injected glucose stimulates a much greater insulin response than ingested glucose.
False. Oral glucose stimulates a greater response than injected glucose.
Name two incretins released from the gastrointestinal tract that stimulate insulin secretion.
Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide hormone (GIP).
Through which signaling molecule and channels found in beta-pancreatic cells do incretins exert their effect?
PKA and potassium/calcium channels.
What is the function of the drug sitagliptin?
It inhibits the protease that degrades incretins, leading to a longer insulin response. It is useful to treat Type II diabetes.
Which family of receptors bind to insulin?
Tyrosine kinases.
How does insulin decrease blood glucose concentrations?
By increasing glucose uptake in muscle and adipose tissue.
What is the effect of insulin on lipoprotein lipase?
It increases lipoprotein lipase activity.
What is the effect of insulin on glycogen phosphorylase and glycogen synthetase?
Insulin decreases the activity of the phosphorylase and increases the activity of the synthetase.
What is the effect of insulin on the gluconeogenic pathway?
It decreases gluconeogenic reactions.
What is the effect of insulin on fatty acid synthesis in the liver?
It increases fatty acid synthesis.
What is the effect of insulin on hormone-sensitive lipase?
It decreases hormone-sensitive lipase activity.
Which glycolytic enzyme is directly regulated by insulin?
Phosphofructokinase-2.
