Diabetes Type 2: Causes and Characteristics

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Questions and Answers

What is the main difference between type 1 and type 2 diabetes in terms of insulin?

Type 1 has insulin resistance, while type 2 has no insulin

Type 1 has low insulin levels, while type 2 has high insulin levels

Type 1 has high insulin levels, while type 2 has low insulin levels

Type 1 has no insulin, while type 2 has insulin resistance (correct)

What is a common complication of diabetes that can lead to blindness?

Neuropathy

Retinopathy (correct)

Microangiopathy

Nephropathy

What is the main mechanism that limits muscle protein breakdown in starvation, but not in diabetes?

KB production

Glucagon release

Insulin release (correct)

FA release from adipocytes

What is a characteristic of type 2 diabetes in terms of ketoacidosis?

It is less common than in type 1 Signup and view all the answers

What is the primary treatment for type 1 diabetes?

Exogenous insulin by injection Signup and view all the answers

What is a common association of type 2 diabetes?

Diet and lifestyle, e.g. obesity Signup and view all the answers

What is the total energy value in kcal of glycogen present in the muscle and liver?

1460 + 330 Signup and view all the answers

In the fasting state, what is the primary source of energy?

Triacylglycerols (TAGs) Signup and view all the answers

What is the concentration of blood glucose maintained by the liver in the fasting state?

4 mM Signup and view all the answers

What is the source of blood glucose after 24 hours of fasting?

Gluconeogenesis Signup and view all the answers

What is the reaction catalyzed by Pyruvate dehydrogenase (PDH)?

Pyruvate to Acetyl-CoA Signup and view all the answers

What is the effect of insulin on Pyruvate dehydrogenase (PDH)?

Activation Signup and view all the answers

What is the fate of excess acetyl-CoA in the fed state?

Channelled into FA synthesis Signup and view all the answers

What is the primary function of hormone sensitive lipase in adipose tissue?

Triglyceride breakdown Signup and view all the answers

What happens to gluconeogenic substrates when FA is used as fuel by liver adipose tissue and muscle?

They are inhibited and conversion to glc is favoured Signup and view all the answers

What is the result of FA oxidation in the hepatocyte?

High concentrations of Acetyl CoA Signup and view all the answers

What happens to body protein in prolonged starvation?

It is severely depleted Signup and view all the answers

What is the fate of ketone bodies in prolonged starvation?

They are recovered from the kidney Signup and view all the answers

What is the effect of ketone bodies on the pancreas?

They stimulate insulin release Signup and view all the answers

What is the outcome of diabetes mellitus?

Blindness, amputations, premature deaths Signup and view all the answers

What is the characteristic of Type 1 diabetes?

Autoimmune destruction of β cells Signup and view all the answers

What is the hallmark of diabetes type 1?

Hyperglycaemia and ketoacidosis Signup and view all the answers

Study Notes

Diabetes Type 2

Usually has a later onset
Characterized by insulin resistance, where target tissues are non-responsive
Typically milder than Type 1 diabetes
Associated with diet and lifestyle, particularly obesity
Incidence is increasing, including in children

Characteristics of Diabetes

Hyperglycaemia, but usually no ketoacidosis
Often responds to diet and oral hypoglycaemic agents

Metabolic Pattern in Uncontrolled Diabetes Mellitus

Resembles that of starvation, but more exaggerated
Insulin is low in starvation, absent in Type 1 diabetes
Glucagon acts unopposed, leading to uncontrolled production of ketone bodies
This important mechanism does not operate in diabetes

Chronic Complications of Diabetes Mellitus

Microangiopathy: changes in small blood vessels, seen as thickening of basement membrane
Retinopathy: blindness is 25 times more common in diabetic patients
Nephropathy: renal failure is 17 times more common
Neuropathy: postural hypotension, impotence, foot ulcers

Treatment of Diabetes

Type 1: exogenous insulin by injection

Total Fuel Reserves in the Average Man

Glycogen: 300g in muscle, 80g in liver, 15g in body fluids
TAG: 15kg in adipose tissue
Protein: 6kg in muscle
Total energy reserve: 697.8MJ

The Fasting (Post-Absorptive) State

Blood glucose concentrations peak an hour after eating and return to normal by two hours after a meal
Blood glucose is removed for oxidation or storage
Concentration of insulin drops and glucagon rises

Metabolism in the Fasting State

Liver maintains blood glucose concentrations at about 4mM
Adipose tissue provides the greatest source of energy as TAGs
Hormone-sensitive lipase is activated by glucagon and adrenaline
FA are transported to the liver bound to albumin

Glucose Production by the Liver

The first supplier of blood glucose is liver glycogen
Gluconeogenesis follows from lactate, glycerol, and amino acids
After 24 hours of fasting, all blood glucose comes from gluconeogenesis

Fatty Acid Metabolism

Fatty acids are not gluconeogenic precursors
The reaction catalyzed by Pyruvate dehydrogenase is irreversible
PDH is activated by insulin and inhibited by glucagon

Ketone Body Formation

FA oxidation in the hepatocyte leads to high concentrations of Acetyl CoA
Acetyl CoA is channelled into ketone body formation
Acetoacetate and β-hydroxybutyrate are released into the bloodstream

Prolonged Fasting (Starvation)

If the early pattern were to continue, body protein would be severely depleted
Only about a third of body protein can be lost without severe or fatal consequences

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Description

This quiz covers the characteristics of diabetes type 2, including its onset, symptoms, and treatment options. Learn about insulin resistance, associations with diet and lifestyle, and the metabolic pattern in uncontrolled diabetes.