OGT Glucose Metabolism and Physiology 2

Question 1

What is the role of the incretin hormone GLP-1 during an oral glucose tolerance test?

Accepted Answer

Enhances glucose-stimulated insulin secretion and suppresses glucagon

Answer

GLP-1 (glucagon-like peptide-1) is released from intestinal L-cells during oral glucose ingestion and amplifies insulin secretion while suppressing glucagon, lowering post-meal glucose.

Question 2

Why does an oral glucose load produce a greater insulin response than the same glucose given intravenously?

Accepted Answer

The incretin effect amplifies pancreatic insulin secretion

Answer

Gut-derived incretin hormones (GLP-1, GIP) released during oral glucose ingestion amplify insulin secretion, producing a greater response than IV glucose — known as the 'incretin effect.'

Question 3

In type 2 diabetes, impaired glucose tolerance is primarily driven by which two defects?

Accepted Answer

Insulin resistance and progressive beta-cell dysfunction

Answer

Type 2 diabetes results from a combination of peripheral insulin resistance (primarily in muscle and liver) and inadequate compensatory insulin secretion due to beta-cell dysfunction.

Question 4

Which substrate does the brain preferentially use for energy, making stable blood glucose critical?

Accepted Answer

Glucose

Answer

Under normal conditions the brain relies almost exclusively on glucose as its energy substrate, requiring tightly regulated blood glucose levels.

Question 5

What is the normal renal glucose threshold at which glucosuria (glucose in urine) appears?

Accepted Answer

~180 mg/dL

Answer

Glucose appears in the urine when plasma glucose exceeds approximately 180 mg/dL, the renal tubular reabsorption threshold.

OGT - Oral Glucose Tolerance Practice Test

OGT - Oral Glucose Tolerance Practice Test

OGT Glucose Metabolism and Physiology 2