p.16
Glucagon Secretion and Function
What is the primary function of glucagon?
To increase blood glucose levels.
p.19
Hypoglycemia Causes and Investigation
How can exercise contribute to hypoglycemia?
By increasing glucose utilization in the body.
p.9
Control of Insulin Secretion
What additional effects does GLP-1 have besides insulin secretion?
Beneficial effects in the control of blood glucose.
p.20
Hypoglycemia Causes and Investigation
What is the purpose of the C-peptide test?
To differentiate the causes of hypoglycemia.
p.18
Control of Insulin Secretion
What condition stimulates insulin release?
High blood glucose (hyperglycemia).
p.7
Control of Insulin Secretion
What happens after the closure of ATP-sensitive K+ channels?
Membrane depolarization activates voltage-gated Ca2+ channels, allowing Ca2+ influx.
p.6
Control of Insulin Secretion
How does growth hormone affect insulin secretion?
It can increase insulin resistance, affecting overall insulin secretion.
p.17
Control of Insulin Secretion
What does sympathetic stimulation do to glucagon secretion?
It stimulates glucagon secretion.
p.13
Effects of Insulin on Metabolism
What role does insulin play in protein metabolism?
Insulin stimulates protein synthesis and inhibits protein breakdown.
p.23
Pathophysiology of Diabetes Mellitus
What causes hyperglycaemia in patients with diabetes mellitus?
Loss of insulin action in stimulating glucose uptake and inhibiting glucose production.
p.25
Diabetic Ketoacidosis (DKA) Pathogenesis
What is the consequence of decreased malonyl CoA levels?
It removes the inhibition on CPT-1, allowing long chain fatty acids to be shuttled for β-oxidation.
p.12
Effects of Insulin on Metabolism
How does insulin affect adipose tissue?
Stimulates glucose uptake for glycolysis and fat synthesis, stimulates lipogenesis, and inhibits lipolysis.
p.3
Endocrine Pancreas Cell Types
What is the function of D (δ) cells in the pancreas?
They secrete somatostatin.
p.13
Effects of Insulin on Metabolism
How does insulin affect fat metabolism?
Insulin promotes the storage of fat and inhibits the breakdown of fat.
p.8
Incretin Effect and Diabetes Management
What does an oral dose of glucose do to insulin secretion compared to intravenous infusion?
It stimulates a greater rise in insulin secretion.
p.17
Effects of Insulin on Metabolism
How do glucagon and catecholamines affect metabolism?
They share most of their metabolic effects.
p.11
Effects of Insulin on Metabolism
What does insulin induce in skeletal muscle cells and adipocytes?
Translocation of glucose transporter (GLUT-4) to the cell surface.
p.15
Glucagon Secretion and Function
What is the effect of glucagon on adipose tissue?
It has a weak lipolytic effect to stimulate lipolysis.
p.23
Pathophysiology of Diabetes Mellitus
What role do stress hormones play in hyperglycaemia?
They stimulate catabolic processes despite the presence of hyperglycaemia.
p.19
Hypoglycemia Causes and Investigation
What are oral hypoglycemic drugs designed to do?
Stimulate insulin secretion from the pancreas.
p.18
Control of Insulin Secretion
Under what conditions are both insulin and glucagon secreted?
Increase in plasma levels of amino acids and parasympathetic stimulation.
p.5
Control of Insulin Secretion
What substances can stimulate insulin secretion at high concentrations?
Ketones and long-chain free fatty acids.
p.2
Pathophysiology of Diabetes Mellitus
What are common symptoms of diabetes mellitus?
Increased thirst, frequent urination, extreme fatigue, and blurred vision.
p.2
Pathophysiology of Diabetes Mellitus
What is the pathogenesis of Type 2 diabetes mellitus?
It involves insulin resistance and eventual beta-cell dysfunction.
p.9
Control of Insulin Secretion
What is one of the primary functions of Glucagon-like peptide (GLP-1)?
Potentiating glucose-induced insulin secretion.
p.15
Glucagon Secretion and Function
What is the overall function of glucagon?
To mobilize carbohydrates and fat as metabolic fuels during low blood glucose levels.
p.11
Effects of Insulin on Metabolism
What is one primary effect of insulin on blood glucose levels?
Insulin lowers blood glucose levels.
p.4
Endocrine Pancreas Cell Types
What is proinsulin processed into?
Mature insulin and C-peptide.
p.20
Hypoglycemia Causes and Investigation
What condition can the C-peptide test help identify?
Insulinoma or endogenous insulin production.
p.8
Control of Insulin Secretion
What is C-peptide and why is it significant?
C-peptide is formed from the cleavage of pro-insulin into insulin and indicates β-cell function and the source of circulating insulin.
p.15
Glucagon Secretion and Function
What are the main actions of glucagon on the liver?
Stimulates glycogenolysis and gluconeogenesis, and promotes ketogenesis.
p.27
Control of Insulin Secretion
How does the sodium-potassium pump affect resting membrane potential?
It pumps 3 Na+ out and 2 K+ in, maintaining the negative charge inside the cell.
p.17
Effects of Insulin on Metabolism
What is the combined effect of catecholamines on blood glucose?
They increase blood glucose levels.
p.16
Glucagon Secretion and Function
What is the feedback mechanism for glucagon secretion?
Increased blood glucose levels inhibit further glucagon release.
p.24
Diabetic Ketoacidosis (DKA) Pathogenesis
What stimulates the increase of counter-regulatory hormones in DKA?
Signals from other precipitating factors.
p.26
Diabetic Ketoacidosis (DKA) Pathogenesis
What is the function of MCD?
Malonyl CoA decarboxylase, involved in fatty acid metabolism.
p.14
Control of Glucagon Secretion
What role do amino acids play in glucagon secretion?
Amino acids from protein intake stimulate glucagon secretion.
p.5
Control of Insulin Secretion
What effect do incretins have on insulin release?
They potentiate insulin release induced by high blood glucose levels.
p.2
Pathophysiology of Diabetes Mellitus
What is hyperosmolar hyperglycemic state (HHS)?
A serious condition in Type 2 diabetes characterized by extremely high blood sugar without significant ketone production.
p.1
Incretin Effect and Diabetes Management
What role do GLP-1 and DPP-4 inhibitors play in diabetes management?
They are used as adjunctive therapy for type 2 diabetes mellitus.
p.6
Control of Insulin Secretion
What stimulates insulin secretion after a meal?
The presence of glucose and other nutrients in the bloodstream.
p.27
Control of Insulin Secretion
What is the resting membrane potential?
The electrical potential difference across the plasma membrane of a resting cell.
p.9
Endocrine Pancreas Cell Types
What does tissue-specific post-translational processing of preproglucagon produce?
GLP-1 in intestinal L cells and glucagon in pancreatic A cells.
p.13
Effects of Insulin on Metabolism
What is the principal effect of insulin on glucose metabolism?
Insulin facilitates the uptake of glucose by cells, lowering blood glucose levels.
p.17
Control of Insulin Secretion
What is the effect of sympathetic stimulation on insulin secretion?
It inhibits insulin secretion.
p.12
Effects of Insulin on Metabolism
What local effect may occur at the injection site of insulin in DM patients?
Insulin-induced lipohypertrophy.
p.16
Glucagon Secretion and Function
How does glucagon affect glycogen in the liver?
It stimulates glycogenolysis, the breakdown of glycogen into glucose.
p.15
Glucagon Secretion and Function
How does glucagon's effect compare to that of insulin?
Glucagon has a catabolic effect, generally opposing that of insulin.
p.24
Diabetic Ketoacidosis (DKA) Pathogenesis
What condition are patients with type 1 diabetes mellitus prone to develop?
Diabetic ketoacidosis (DKA).
p.27
Control of Insulin Secretion
What ions primarily influence the resting membrane potential?
Sodium (Na+) and potassium (K+).
p.15
Glucagon Secretion and Function
What does the molar ratio of insulin to glucagon indicate?
It gives a better indication of their relative activities in the blood.
p.25
Diabetic Ketoacidosis (DKA) Pathogenesis
What effect does glucagon have in the absence of insulin?
It leads to the inhibition of acetyl CoA carboxylase, resulting in a drop in malonyl CoA levels.
p.18
Control of Insulin Secretion
What role do amino acids play in insulin release?
They stimulate insulin release from protein intake.
p.28
Haemoglobin A1c and Diabetes Monitoring
What is HbA1c a marker for?
Long-term glucose regulation.
p.24
Diabetic Ketoacidosis (DKA) Pathogenesis
What state leads to the development of DKA in type 1 diabetes?
Absolute or severe insulin deficiency.
p.4
Control of Insulin Secretion
What does C-peptide concentration in blood indicate?
It provides information on β-cell function and endogenous secretion versus exogenous injection.
p.16
Glucagon Secretion and Function
What triggers the secretion of glucagon?
Low blood glucose levels.
p.7
Control of Insulin Secretion
What triggers the exocytosis of insulin-containing secretory vesicles?
The influx of Ca2+ following membrane depolarization.
p.18
Control of Insulin Secretion
What type of stimulation can trigger insulin release?
Parasympathetic stimulation (e.g., food intake).
p.19
Hypoglycemia Causes and Investigation
What effect does fasting have on blood sugar levels?
It can lead to hypoglycemia.
p.23
Pathophysiology of Diabetes Mellitus
What processes are increased due to the loss of insulin action in diabetes?
Glycogenolysis and gluconeogenesis.
p.11
Effects of Insulin on Metabolism
What is the role of glucokinase in relation to insulin?
Insulin induces glucokinase expression in hepatocytes.
p.7
Control of Insulin Secretion
What is the role of sulphonylurea drugs in insulin secretion?
They bind to sulphonylurea receptor (SUR-1), causing closure of ATP-sensitive potassium channels.
p.18
Glucagon Secretion and Function
What condition stimulates glucagon release?
Low blood glucose (hypoglycemia).
p.25
Diabetic Ketoacidosis (DKA) Pathogenesis
What happens to hormone sensitive lipase in the absence of insulin?
It is no longer inhibited, allowing increased lipolysis to generate fatty acids.
p.16
Glucagon Secretion and Function
What process does glucagon promote to increase glucose production?
Gluconeogenesis, the synthesis of glucose from non-carbohydrate sources.
p.12
Effects of Insulin on Metabolism
What processes does insulin inhibit in the liver?
Glycogenolysis, gluconeogenesis, and ketogenesis.
p.20
Hypoglycemia Causes and Investigation
How does the C-peptide level relate to hypoglycemia?
Low C-peptide levels suggest exogenous insulin use, while high levels indicate endogenous insulin production.
p.13
Control of Insulin Secretion
What happens to insulin secretion when blood glucose levels drop?
Insulin secretion decreases to prevent further lowering of blood glucose levels.
p.28
Haemoglobin A1c and Diabetes Monitoring
What happens to haemoglobin once glycation occurs?
It remains glycated for the remainder of the RBC’s life span.
p.20
Hypoglycemia Causes and Investigation
What does a low C-peptide level indicate in a hypoglycemic patient?
It suggests that the hypoglycemia is due to exogenous insulin administration.
p.11
Effects of Insulin on Metabolism
Which tissues are primarily responsive to insulin for glucose uptake?
Skeletal muscle and adipose tissue.
p.8
Control of Insulin Secretion
What is the role of the hepatic portal circulation in insulin and C-peptide release?
Insulin and C-peptide are released from the pancreas and first presented to the liver via the hepatic portal circulation.
p.2
Pathophysiology of Diabetes Mellitus
What is diabetes mellitus?
A chronic condition characterized by high blood sugar levels due to insulin resistance or insufficient insulin production.
p.22
Pathophysiology of Diabetes Mellitus
What causes osmotic diuresis?
High levels of glucose in the blood leading to increased urine production.
p.1
Control of Insulin Secretion
What is the cellular mechanism behind glucose-induced insulin secretion?
Involves specific cellular pathways triggered by glucose.
p.7
Control of Insulin Secretion
How does glucose stimulate insulin secretion in pancreatic β-cells?
Through intracellular generation of ATP, which causes closure of ATP-sensitive K+ (K ATP) channels.
p.12
Effects of Insulin on Metabolism
What processes does insulin stimulate in the liver?
Glycogenesis and glycolysis.
p.27
Control of Insulin Secretion
What role do ion channels play in resting membrane potential?
They allow specific ions to flow in and out of the cell, contributing to the potential difference.
p.4
Effects of Insulin on Metabolism
In what ratio is C-peptide formed with insulin?
In equimolar concentration.
p.25
Diabetic Ketoacidosis (DKA) Pathogenesis
What is the role of CPT-1 in fatty acid metabolism?
CPT-1 facilitates the transport of long chain fatty acids from the cytosol to the mitochondrial matrix for β-oxidation.
p.11
Effects of Insulin on Metabolism
How does insulin affect hepatic glucose production?
It inhibits hepatic glucose production through glycogenolysis and gluconeogenesis.
p.23
Pathophysiology of Diabetes Mellitus
Which hormones are considered stress hormones that affect glucose metabolism?
Cortisol, catecholamines, and glucagon.
p.19
Hypoglycemia Causes and Investigation
What is insulinoma?
A condition characterized by hypersecretion of insulin.
p.10
Effects of Insulin on Metabolism
What role does insulin play in amino acid uptake?
It promotes amino acid uptake and protein synthesis.
p.2
Hyperglycemia Causes and Investigation
What is hyperglycemia?
A condition of elevated blood glucose levels, often leading to catabolism.
p.22
Pathophysiology of Diabetes Mellitus
What is hyperglycemia?
A condition characterized by elevated blood glucose levels.
p.1
Endocrine Pancreas Cell Types
What is the process of converting proinsulin to insulin?
Post-translational processing.
What are the effects of glucagon?
Glucagon increases blood glucose levels by promoting glycogenolysis and gluconeogenesis.
p.11
Effects of Insulin on Metabolism
How does insulin facilitate glucose utilization?
By stimulating glucose uptake for glycolysis and storage through glycogenesis.
p.17
Effects of Insulin on Metabolism
What is a key difference between glucagon and epinephrine regarding skeletal muscle?
Glucagon has no effect on skeletal muscle in stimulating glycogenolysis.
p.8
Oral Glucose Tolerance Test (OGTT)
What does the Oral Glucose Tolerance Test (OGTT) measure?
It tests for the maximum insulin secretory response in controlling blood glucose levels.
p.20
Hypoglycemia Causes and Investigation
What does a high C-peptide level indicate in a hypoglycemic patient?
It suggests that the body is producing insulin, possibly due to an insulinoma.
p.7
Incretin Effect and Diabetes Management
How does incretin (e.g., GLP-1) amplify glucose-induced insulin release?
Through cross-talk of two different second messenger systems: increase in intracellular [Ca2+] and cAMP/PKA/protein phosphorylation.
p.5
Control of Insulin Secretion
Which amino acids can stimulate insulin secretion?
Amino acids from protein intake.
p.19
Hypoglycemia Causes and Investigation
How does alcohol consumption affect glucose production?
It inhibits endogenous glucose production, potentially leading to hypoglycemia.
p.26
Diabetic Ketoacidosis (DKA) Pathogenesis
How does increased gluconeogenesis affect the citric acid cycle?
It depletes citric acid cycle intermediates like oxaloacetate.
p.2
Diabetic Ketoacidosis (DKA) Pathogenesis
What is diabetic ketoacidosis (DKA)?
A serious complication of Type 1 diabetes characterized by high blood sugar, ketone production, and acidosis.
p.2
Haemoglobin A1c and Diabetes Monitoring
What are advanced glycation end-products (AGEs)?
Compounds formed when sugar molecules bind to proteins or lipids, contributing to diabetic complications.
p.22
Pathophysiology of Diabetes Mellitus
What is hyperlipidemia?
Elevated levels of lipids in the blood.
p.1
Effects of Insulin on Metabolism
What are the effects of insulin on metabolism?
Insulin promotes glucose uptake, fat storage, and protein synthesis.
p.1
Hypoglycemia Causes and Investigation
What are possible causes of hypoglycemia?
Insulin overdose, prolonged fasting, and certain medications.
p.13
Control of Insulin Secretion
What is the feedback control mechanism for insulin secretion?
Insulin secretion is regulated by blood glucose levels; high glucose stimulates insulin release.
p.16
Glucagon Secretion and Function
What role does insulin play in glucagon secretion?
Insulin inhibits glucagon secretion.
p.24
Diabetic Ketoacidosis (DKA) Pathogenesis
What processes are inhibited by insulin that are lifted in DKA?
Hormone sensitive lipase, lipolysis, ketogenesis, and gluconeogenesis.
p.10
Effects of Insulin on Metabolism
In which tissues does insulin promote storage?
Mainly in liver/muscle for carbohydrates and protein, and in adipose tissue for fat.
p.14
Control of Glucagon Secretion
What stimulates glucagon secretion?
Low blood glucose (hypoglycemia), amino acids from protein intake, and parasympathetic/sympathetic stimulation.
p.26
Diabetic Ketoacidosis (DKA) Pathogenesis
What happens to fatty acids in the mitochondrial matrix?
They undergo β-oxidation to form ketone bodies.
p.26
Diabetic Ketoacidosis (DKA) Pathogenesis
What is the rate-limiting step for transporting long chain fatty acids into the mitochondria?
Trans-esterification to fatty acyl carnitine by CPT1.
p.5
Control of Insulin Secretion
Which catecholamines inhibit insulin secretion?
Norepinephrine and epinephrine.
p.1
Endocrine Pancreas Cell Types
What types of autonomic control affect the endocrine pancreas?
Sympathetic and parasympathetic control.
p.22
Pathophysiology of Diabetes Mellitus
What is the underlying cause of diabetes mellitus?
Insulin deficiency or resistance to insulin action.
p.10
Effects of Insulin on Metabolism
What processes does insulin promote in the fed state?
Storage of carbohydrates (glycogenesis), fat (lipogenesis), and protein (protein synthesis).
p.18
Glucagon Secretion and Function
How do amino acids affect glucagon release?
They stimulate glucagon release from protein intake.
p.8
Control of Insulin Secretion
Why is C-peptide a useful marker in assessing insulin secretion?
Because it is not extracted by hepatocytes and provides information on whether insulin is from endogenous secretion or exogenous injection.
p.4
Pathophysiology of Diabetes Mellitus
What does the alternative 'constitutive pathway' release?
Large amounts of unprocessed proinsulin.
p.5
Control of Insulin Secretion
What type of nerve stimulation can enhance insulin secretion?
Parasympathetic/vagal nerve stimulation via acetylcholine.
p.5
Control of Insulin Secretion
What are incretins?
GI hormones that amplify glucose-induced insulin release.
p.26
Diabetic Ketoacidosis (DKA) Pathogenesis
How is fatty acyl carnitine converted back to fatty acyl CoA?
By carnitine palmitoyl transferase II (CPT II) on the inner mitochondrial membrane.
p.2
Haemoglobin A1c and Diabetes Monitoring
How does Haemoglobin A1c relate to diabetes?
It measures average blood glucose levels over the past 2-3 months, indicating long-term glucose control.
p.22
Pathophysiology of Diabetes Mellitus
What are common symptoms of type 1 diabetes mellitus?
Muscle wasting and weight loss.
p.8
Control of Insulin Secretion
How does endogenous production of insulin relate to C-peptide?
In endogenous production, proinsulin is processed by β-cells to generate insulin and C-peptide in equimolar concentrations.
p.26
Diabetic Ketoacidosis (DKA) Pathogenesis
What is the role of AMPK?
AMP-activated kinase involved in cellular energy regulation.
p.18
Glucagon Secretion and Function
What type of stimulation can trigger glucagon release?
Parasympathetic stimulation (e.g., food intake).
p.10
Effects of Insulin on Metabolism
What is lipogenesis?
The process of fat storage promoted by insulin.
p.10
Effects of Insulin on Metabolism
How does insulin affect potassium ions (K+)?
It promotes the uptake of K+ ions.
p.2
Pathophysiology of Diabetes Mellitus
What is the pathogenesis of Type 1 diabetes mellitus?
It involves autoimmune destruction of insulin-producing beta cells in the pancreas.
p.1
Incretin Effect and Diabetes Management
What is the incretin effect?
The enhanced insulin secretion in response to oral glucose.
p.1
Control of Insulin Secretion
What conditions can stimulate both insulin and glucagon secretion?
Stress and certain metabolic states.
p.10
Effects of Insulin on Metabolism
What metabolic processes does insulin inhibit?
Processes that operate under the catabolic state, including gluconeogenesis, glycogenolysis, lipolysis, ketogenesis, and proteolysis.
p.14
Control of Glucagon Secretion
What are the inhibitors of glucagon secretion?
High blood glucose, insulin, GLP-1, and somatostatin.
p.5
Control of Insulin Secretion
Which incretins are known to amplify insulin release?
Glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP).
p.1
Oral Glucose Tolerance Test (OGTT)
What test is used to assess glucose tolerance?
Oral Glucose Tolerance Test (OGTT).
p.12
Effects of Insulin on Metabolism
What effects does insulin have on skeletal muscle?
Stimulates glucose and amino acid uptake for glycolysis, glycogen, and protein synthesis, and inhibits protein breakdown.
p.24
Diabetic Ketoacidosis (DKA) Pathogenesis
What drives the accelerated levels of lipolysis and gluconeogenesis in DKA?
Increased levels of counter-regulatory hormones.
p.23
Pathophysiology of Diabetes Mellitus
What are the catabolic processes that occur during stress in diabetes?
Gluconeogenesis, glycogenolysis, lipolysis, ketogenesis, and proteolysis.
p.26
Diabetic Ketoacidosis (DKA) Pathogenesis
What is the role of carnitine-acylcarnitine translocase (CAT)?
It transports fatty acyl carnitine across the inner mitochondrial membrane.
p.22
Pathophysiology of Diabetes Mellitus
What is glucosuria?
The presence of glucose in urine.
p.1
Control of Insulin Secretion
What are the three categories that control insulin secretion?
Stimulants, amplifiers, and inhibitors.
p.1
Control of Glucagon Secretion
How does insulin control glucagon secretion?
Insulin inhibits glucagon secretion.
p.23
Control of Insulin Secretion
What are the effects of insulin on glucose metabolism?
Stimulates glucose uptake, glycolysis, glycogen synthesis, amino acid uptake, and lipogenesis.
p.14
Control of Glucagon Secretion
Which sympathetic stimulation affects glucagon secretion?
Sympathetic stimulation via β2 receptors (i.e., stress).
p.14
Control of Glucagon Secretion
How does low blood glucose affect glucagon secretion?
It stimulates glucagon secretion.
p.5
Control of Insulin Secretion
What inhibits insulin secretion?
Low blood glucose levels.
p.22
Diabetic Ketoacidosis (DKA) Pathogenesis
What is ketoacidosis in type 1 diabetes mellitus?
A serious condition resulting from insulin deficiency, leading to the production of ketones.
p.1
Hypoglycemia Causes and Investigation
What is the algorithm for investigating hypoglycemia?
Involves assessing symptoms, blood glucose levels, and potential causes.
p.1
Endocrine Pancreas Cell Types
What is an example of intra-islet interaction?
Inhibition of glucagon secretion by insulin.
p.22
Pathophysiology of Diabetes Mellitus
What is glycosuria?
The presence of reducing sugars in urine.
