CPPS303 XIAO Lecture 7 Gut Hormones March_24_2025 (1)

Question 1

What is one of the learning objectives of the lecture on Gut Hormones?

Answer 1

Describe the secretion of gut hormones

Question 2

What do gut hormones regulate?

Answer 2

Nutrient absorption and glucose metabolism

Question 3

Which cell type in the gut epithelium is responsible for nutrient absorption?

Answer 3

Surface absorptive cell (enterocyte)

Question 4

What do goblet cells in the gut secrete?

Answer 4

Mucin to create a protective mucus layer

Question 5

What is the function of enteroendocrine cells?

Answer 5

Secrete gut hormones

Question 6

What do Paneth cells secrete?

Answer 6

Anti-microbial peptides (defensins)

Question 7

Which hormone is secreted by I cells in the duodenum?

Answer 7

Cholecystokinin (CCK)

Question 8

What is the primary action of Gastrin?

Answer 8

↑ H+ secretion in the stomach

Question 9

Fill in the blank: GIP stands for _______.

Answer 9

Gastric inhibitory peptide (glucose-dependent insulinotropic polypeptide)

Question 10

True or False: Secretin decreases gastric acid secretion.

Answer 10

True

Question 11

What effect does motilin have?

Answer 11

↑ Smooth-muscle contraction

Question 12

Which hormone is released by S cells in the small intestine?

Answer 12

Secretin

Question 13

What does somatostatin do in the pancreas?

Answer 13

↓ Endocrine/exocrine secretions

Question 14

What type of receptors do enteroendocrine cells respond to?

Answer 14

Luminal receptors for SCFAs and BAs

Question 15

How is gut hormone secretion stimulated?

Answer 15

By circulating hormones, glucose, or enteric nerve stimulation

Question 16

What is the entero-insular axis?

Answer 16

The connection between gut and pancreatic islets

Question 17

What is the incretin effect?

Answer 17

Higher insulin secretory response with oral vs intravenous glucose administration

Question 18

What does GLP-1 stand for?

Answer 18

Glucagon-like peptide-1

Question 19

What is the primary role of incretins?

Answer 19

Enhance glucose-stimulated insulin secretion

Question 20

True or False: Insulin secretion from beta-cells is greater after oral glucose compared to intravenous glucose.

Answer 20

True

Question 21

What happens when glucose is ingested?

Answer 21

Stimulates incretin secretion and insulin secretion

Question 22

What are the products of proglucagon cleavage in intestinal enteroendocrine cells?

Answer 22

Glicentin, IP-2, GLP-1, GLP-2

Question 23

Fill in the blank: Enteroendocrine cells can act in a _______ manner with neighboring enterocytes.

Answer 23

Paracrine

Question 24

What is the Incretin Effect?

Answer 24

The Incretin Effect refers to the enhanced insulin secretion in response to glucose ingestion due to gut hormones.

Incretin hormones include GIP and GLP-1, which are secreted from enteroendocrine cells in the gut.

Question 25

What role do glucose transporters like SGLT1 play in glucose absorption?

Answer 25

Glucose transporters such as SGLT1 facilitate glucose absorption across the intestinal epithelium. ## Footnote SGLT1 is primarily responsible for the uptake of glucose in the intestines.

Question 26

What happens to plasma glucose concentrations after glucose ingestion?

Answer 26

Plasma glucose concentrations elevate following glucose ingestion. ## Footnote This elevation triggers further physiological responses, including insulin secretion.

Question 27

How does elevated plasma glucose concentration affect pancreatic β-cells?

Answer 27

It leads to an increase in cytoplasmic [Ca2+] in insulin-secreting pancreatic β-cells, resulting in increased insulin secretion. ## Footnote Elevated calcium levels in β-cells are crucial for the exocytosis of insulin.

Question 28

What triggers the secretion of GIP and GLP-1?

Answer 28

Glucose crossing the apical membrane of K cells or L cells via SGLT1 triggers the secretion of GIP and GLP-1. ## Footnote K cells primarily secrete GIP, while L cells secrete GLP-1.

Question 29

What is the role of GIPR and GLP1R on β-cells?

Answer 29

GIPR and GLP1R are coupled to increased levels of cAMP via G-proteins, amplifying insulin secretion when activated by rising glucose levels. ## Footnote cAMP acts as a secondary messenger that enhances the signaling pathways for insulin release.

Question 30

What are the main functions of gut hormones like GLP-1 and GIP?

Answer 30

Gut hormones regulate nutrient absorption and promote insulin secretion in response to food intake. ## Footnote They play a significant role in glucose metabolism and appetite regulation.

Question 31

Fill in the blank: The incretin effect is primarily mediated by _______.

Answer 31

GLP-1 and GIP.

Question 32

True or False: The incretin effect enhances insulin secretion only when glucose levels are low.

Answer 32

False. ## Footnote The incretin effect enhances insulin secretion specifically when glucose levels are elevated.

Question 33

What are incretin-based therapeutics primarily targeting?

Answer 33

Incretin-based therapeutics primarily target the functions of GLP-1 and GIP to improve glycemic control. ## Footnote These therapeutics are commonly used in the management of type 2 diabetes.

Question 34

List the multiple functions of GLP-1.

Answer 34

* Enhancing insulin secretion * Inhibiting glucagon secretion * Slowing gastric emptying * Reducing appetite ## Footnote These functions contribute to overall glucose homeostasis.