Glucose Tolerance Test Lab

Question 1

What hormones affect gluconeogenesis or glycogenolysis or glucose-uptake by cells?

Answer 1

Growth hormone, adrenaline, glucagon, somatostatin, thyroid hormones, cortisol (to name just some). Make sure you know how each of these hormones interacts with the normal glucose homeostasis pathways.

Question 2

Describe thencriteria for diagnosing Diabetes mellitus.

Answer 2

Fasting plasma glucose:
≥ 7.0 mmol/L
or
2-h plasma glucose after ingestion of 75g glucose:
≥11.1 mmol/L

Question 3

Describe the criteria for diagnosing Impaired glucose tolerance.

Answer 3

Fasting plasma glucose:
≥ 7.0 mmol/L
and
2-h plasma glucose after ingestion of 75g glucose:
≥7.8 and < 11.1 mmol/L

Question 4

Describe the criteria for diagnosing Impaired

fasting glucose.

Answer 4

Fasting plasma glucose:
6.1 – 6.9 mmol/L
and
2-h plasma glucose after ingestion of 75g glucose:
<7.8 mmol/L

Question 5

Describe the criteria for diagnosing Gestational Diabetes mellitus.

Answer 5

Fasting plasma glucose:
≥ 5.6 mmol/L
or
2-h plasma glucose after ingestion of 75g glucose:
≥7.8 mmol/L

Question 6

What is HbA1c?

Answer 6

The level of glycated haemoglobin (HbAIc) is proportional to the levels of glucose in the blood over a period of approximately 3 months. To answer when it might be good to test Elizabeth again, think how long a red blood cell lasts (~120 days)(and therefore how long it would be before you are testing new Hb)

Question 7

What is DPP-4?

Answer 7

DPP-4 inhibitors work by blocking the action of DPP-4, an enzyme which destroys GLP-1 (an incretin). Incretins help the body produce more insulin only when it is needed and reduce the amount of glucose being produced by the liver when it is not needed. These hormones are released throughout the day and levels are increased at meal times.

Question 8

How do sulphonylureas help in the treatment of diabetes mellitus?

Answer 8

These drugs act on β-cells and inhibit the ATP-sensitive K+ channel.

Question 9

What type of drug is metformin? Which cell type(s) does it act on? What is its mechanism of action?

Answer 9

Biguanide. Causes an increase in the uptake of glucose in skeletal muscle and in liver, it increases insulin sensitivity, it increases the storage of glucose and decreases gluconeogenesis. It also decreases glucose uptake from the gut and suppresses appetite (making it useful to use with sulphonlyureas which increase appetite)

Question 10

What are GLP-1 agonists acting on? How does this help with the control of glucose homeostasis?

Answer 10

GLP-1 receptor on β-cells. Only useful if glucose is present as it uses ATP to make cAMP. Ultimately (check the detail in your pharmacology lectures) this intensifies insulin secretion.

Question 11

What is NPH insulin?

Answer 11

NPH insulin is an insulin with an intermediate duration of action. NPH stands for neutral protamine Hagedorn insulin. It is insulin which has been made intermediate-acting by adding a protein (protamine) in complex with zinc.

Question 12

Describe the recommended target levels for fasting plasma glucose, 1hr post prandial and 2hr post prandial in gestational diabetes.

Answer 12

5. 3 mmol/L
6. 8 mmol/L
7. 4 mmol/L