Pancreatic endocrinology Flashcards
What cells release glucagon?
alpha cells of islet of Langerhans
What cells release insulin?
beta cells of islet of Langerhans
Glucose associated with a meal triggers the release of ______ and reduces the level of _______.
Glucose associated with a meal triggers the release of insulin and reduces the level of glucagon.
What effect does increased plasma insulin have on muscle cells?
- increase glucose uptake and utilization
- net glycogen synthesis
- net amino acid uptake
- net protein synthesis
What effect does increased plasma insulin have on adipocytes?
- increase glucose uptake and utilization
- net triglyceride synthesis
What effect does increased plasma insulin have on hepatocytes?
- increase glucose uptake
- net glycogen synthesis
- net triglyceride synthesis
- no ketone synthesis
What effect does decreased plasma insulin have on muscle cells?
- decrease glucose uptake and utilization
- net glycogen catabolism
- net protein catabolism
- net amino acid release
- fatty acid uptake and utilization
What effect does decreased plasma insulin have on adipocytes?
- decrease glucose uptake and utilization
- net triglyceride catabolism and release of glycerol and fatty acids
What effect does decreased plasma insulin have on hepatocytes?
- increase glucose release due to net glycogen catabolism and gluconeogenesis
- increase ketone synthesis and release
Name three other messengers that influence insulin release besides glucose, and their effect (stimulate, inhibit).
CCK, ACh: stimulate
Somatostatin, epi: inhibit
Glucagon, GIP: stimulate
What is the trigger for glucagon release?
drop in plasma glucose
Where does glucagon have its effect?
liver
What effect does increased plasma glucagon have on the liver?
- increase glycogenolysis (glycogen breakdown)
- increase gluconeogenesis
- increase ketone synthesis
The brain can utilize fatty acids as an energy source.
T/F
FALSE. Brain highly prefers glucose; can use ketones if necessary. NOT fatty acids.
How does increased plasma glucose lead to insulin release?
- glucose enters beta cell via GLUT2 transporter
- that glucose is used to create ATP
- increased level of ATP causes a potassium channel to close
- closure of potassium channel causes membrane to become more positive
- voltage-gated calcium channel opens
- influx of calcium causes insulin granules to merge with cell membrane, and insulin is released
Formation of glucose by the liver (& kidneys) from pyruvate, lactate, glycerol, & amino acids is called what?
gluconeogenesis
What effect does decreased plasma glucose have on the adrenal medulla?
triggers epinephrine secretion
What effect does increased plasma epinephrine have on skeletal muscle?
increase glycogenolysis
What effect does increased plasma epinephrine have on hepatocytes?
- increase glycogenolysis
- increase gluconeogenesis
What effect does increased plasma epinephrine have on adipocytes?
increase lipolysis
What is the net result of increased plasma epinephrine?
- increased plasma glucose
- increased plasma fatty acids
- increased plasma glycerol
What is the net result of increased plasma glucagon?
- increased plasma glucose
- increased plasma ketones
What effect does increased plasma amino acids have on pancreatic islet beta cells?
increased insulin secretion
How is cortisol important for the postabsorptive state?
basal concentrations are permissive for stimulation of gluconeogenesis and lipolysis in the postabsorptive state
