18 Questions
Which hormone is primarily responsible for maintaining blood glucose levels during fasting?
Glucagon
What is the main physiological role of glucagon in glucose homeostasis?
Increasing blood glucose levels
Which of the following hormones is considered an 'anti-insulin' hormone and acts to increase blood glucose levels?
All of the above
What is the primary function of the liver enzyme glucokinase?
To efficiently phosphorylate glucose when levels are high
Which of the following is a key mechanism by which glucagon maintains blood glucose levels during fasting?
Stimulating gluconeogenesis in the liver
What is the primary metabolic state in which glucagon secretion is increased?
During fasting
Which hormone is secreted by the pancreatic beta cells in response to high blood glucose levels, stimulating glucose uptake by skeletal muscle?
Insulin
Which hormone secreted by the gut in response to a meal decreases glucagon secretion and inhibits gastric emptying?
Glucagon-like peptide 1 (GLP-1)
Which enzyme rapidly inactivates the incretin hormones GLP-1 and GIP?
Dipeptidyl peptidase-4 (DPP-4)
What is the primary function of the hormone amylin, which is secreted by the pancreatic beta cells?
Induce a feeling of satiety and decrease appetite
Which hormone secreted by the pancreatic alpha cells plays a key role in increasing blood glucose levels?
Glucagon
At what approximate blood glucose level does glucose stimulate insulin secretion from the pancreatic beta cells?
$> 70$ mg/dL
Which of the following is the rate-limiting step that controls glucose-regulated insulin secretion?
Glucose phosphorylation by glucokinase
What is the primary mechanism by which glucose stimulates insulin secretion in β-cells?
Inhibition of the ATP-sensitive K+ channel, leading to membrane depolarization and calcium influx
Which of the following is NOT a component of the ATP-sensitive K+ channel in β-cells?
A binding site for incretin hormones like GLP-1
What is the primary function of incretin hormones, such as GLP-1, in relation to insulin and glucagon secretion?
Stimulate insulin secretion and decrease glucagon secretion
What is the fate of insulin after it is secreted into the portal venous system?
Approximately 50% of the insulin is degraded by the liver
Which of the following is NOT a consequence of insulin binding to its receptor in target tissues?
Inhibition of glycogen synthesis
Learn about the process of glucose-stimulated insulin secretion in β-cells, starting with glucose transport, phosphorylation by glucokinase, and ATP generation through glycolysis. Explore the regulation of ATP-sensitive K+ channels by ATP, and their interaction with oral hypoglycemic drugs like sulfonylureas and meglitinides.
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