Physiology of Glucose Regulation

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Questions and Answers

What is the normal range of fasting blood glucose?

< 80 mg/dL

< 150 mg/dL

< 120 mg/dL

< 100 mg/dL (correct)

The liver plays a minor role in maintaining blood glucose.

False

What is the main function of insulin in glucose homeostasis?

to lower blood glucose

The organs mainly concerned with glucose storage and release are: liver, muscles, ______________, and kidney.

adipose tissue Signup and view all the answers

Reactive hypoglycaemia is often related to the absolute value of blood glucose rather than the rate of fall.

False Signup and view all the answers

Match the hormones with their functions in glucose homeostasis:

Insulin = lowers blood glucose Glucagon = raises blood glucose GH = raises blood glucose Adrenaline = raises blood glucose Signup and view all the answers

What is the primary difference between Hyperosmolar Hyperglycaemic State (HHS) and Diabetic Ketoacidosis (DKA)?

Presence of ketosis Signup and view all the answers

What is the venous plasma glucose level that indicates hypoglycaemia?

< 50 mg/dL Signup and view all the answers

In Hyperosmolar Hyperglycaemic State (HHS), the plasma osmolality is typically greater than _______________________ mosm/kg.

320 Signup and view all the answers

Match the following causes of hypoglycaemia with their respective categories:

Insulin overdose = Reactive hypoglycaemia Endocrine disorders = Fasting hypoglycaemia Galactosaemia = Reactive hypoglycaemia Liver disease = Fasting hypoglycaemia Signup and view all the answers

What is the treatment for Hyperosmolar Hyperglycaemic State (HHS)?

Administration of fluids and insulin Signup and view all the answers

In Hyperosmolar Hyperglycaemic State (HHS), ketosis is usually present.

False Signup and view all the answers

In the management of hypoglycaemia, I.V _______________________ may be administered instead of normal saline.

5% dextrose Signup and view all the answers

What is the effect of insulin on glycogenolysis in the liver?

Inhibits it Signup and view all the answers

Type 1 diabetes can only occur in young non-obese subjects.

False Signup and view all the answers

What is the enzyme responsible for inactivating GLP-1 and GIP in the circulation?

Dipeptidyl peptidase-4 enzyme (DPP-4) Signup and view all the answers

The primary function of GLP-1 is to increase the release of ______________.

insulin Signup and view all the answers

What is a common symptom of type 1 diabetes?

Weight loss Signup and view all the answers

Match the following tissues with the process activated by insulin:

Liver = Synthesis of glycogen Muscle = Uptake of glucose Adipose = Uptake of chylomicrons and VLDLs Signup and view all the answers

Insulin stimulates ketone body formation.

False Signup and view all the answers

What is the treatment for type 1 diabetes?

Insulin replacement therapy Signup and view all the answers

Study Notes

Vagal Stimulation and Glucose Regulation

Vagal stimulation releases GLP-1 and GIP, which are inactivated by dipeptidyl peptidase-4 (DPP-4) enzyme.
GLP-1 and GIP stimulate insulin release and decrease glucose levels.
Insulin promotes glycogen synthesis, protein synthesis, and triglyceride synthesis in the liver, and glucose uptake in muscles and adipose tissue.

Effects of Insulin on Cellular Metabolism

In the liver, insulin stimulates glycogen synthesis, protein synthesis, and triglyceride synthesis, and inhibits glycogenolysis, gluconeogenesis, and ketone body formation.
In muscles, insulin stimulates glucose uptake and glycogen synthesis, and inhibits glycogenolysis.
In adipose tissue, insulin stimulates glucose uptake and utilization, and inhibits lipolysis.

Type 1 Diabetes

Type 1 diabetes is characterized by little or no insulin secretion.
It is an autoimmune condition with genetic and environmental factors.
It can occur at any age, but usually presents acutely in young, non-obese individuals.
Symptoms include polyuria, thirst, glycosuria, weight loss, and ketoacidosis.

Hyperosmolar Hyperglycaemic State (HHS)

HHS occurs in older patients, usually with type 2 diabetes.
It develops slowly over days, leading to extreme dehydration and hyperglycaemia (>50mmol/L).
Treatment involves administration of fluids and insulin.

Hypoglycaemia

Hypoglycaemia is defined as a venous plasma glucose level < 50 mg/dL.
It is often related to the rate of fall in blood glucose rather than the absolute value.
Categories include reactive hypoglycaemia and fasting hypoglycaemia.

Reactive Hypoglycaemia

Causes of reactive hypoglycaemia include:
- Insulin overdose
- Sulfonylureas
- Salicylate overdose in children
- Poisons
- Galactosaemia
- Hereditary fructose intolerance
- Alcohol intake
- Idiopathic factors

Fasting Hypoglycaemia

Causes of fasting hypoglycaemia include:
- Enhanced glucose utilisation due to endogenous insulin overproduction
- Defective glucose production due to:
  - Endocrine disorders
  - Liver disease
  - Renal disease
  - Miscellaneous factors such as severe malnutrition, starvation, glycogen storage disease, etc.