Non-endocrine gland endocrinology

Question 1

What are the incretins?

Answer 1

Gastric-inhibitory peptide (GIP)
Glucagon like peptide (GLP-1)

Question 2

Where is gastrin produced from?

Answer 2

G cells in duodenum and stomach

Question 3

What is the stimuli that causes gastrin secretion?

Answer 3

Presence of peptides and AAs in gastric lumen
Stomach distension
Vagal stimulation
Hypercalcaemia

Question 4

What are the major effects of gastrin?

Answer 4

Stimulates release of gastric acid from parietal call - decreased pH
Stimulates release of pepsinogen from chief cells

Question 5

Why is gastric secretion inhibited at ~pH3

Answer 5

Further decrease in pH can cause gastric ulceration

Question 6

What is the clinical relevance of gastrin in cats and dogs

Answer 6

Gastrinomas - tumours in gastric secreting cells
Leads to excessive gastrin production => vomiting, inappetance, abdominal pain

Question 7

Where is secretin produced?

Answer 7

duodenum

Question 8

What stimuli causes secretin secretion?

Answer 8

H+ in SI/acid from stomach

Question 9

What is the major effect of secretin?

Answer 9

Stimulates release of bicarbonate-rich pancreatic and biliary fluid to buffer gastric acid

Question 10

Where is cholecystokinin (CKK) produced?

Answer 10

duodenum
Brain cells

Question 11

What is the stimuli for CCK (cholecystokinin) release?

Answer 11

fatty acids, monoglycerides and AAs in SI
Expansion of stomach after meal => CCK in brain

Question 12

Where is gastric inhibitory polypeptide (GIP) produced?

Answer 12

Proximal SI

Question 13

What is the stimuli that causes the secretion of GIP (gastric inhibitory polypeptide)?

Answer 13

Fat, glucose and AAs in SI

Question 14

What are the major effects of GIP (gastric inhibitory polypeptide)?

Answer 14

Inhibits gastric secretion and motility
Increases release of insulin in response to elevated blood glucose levels
Increases insulin sensitivity of adipocytes
Stimulation of lipoprotein lipase activity in adipocytes

Question 15

Where is GLP-1 (glucagon like peptide) produced?

Answer 15

L-cells of ileum and jejunum

Question 16

What stimulates GLP-1 (glucagon like peptide) secretion?

Answer 16

CHO, fat and protein in SI

Question 17

What is the effect of GLP-1 (glucagon like peptide)

Answer 17

Promotes insulin secretion
Suppresses glucagon driven gluconeogenesis
Slows gastric emptying
Promotes satiety/fullness in hypothalamus

Question 18

Where is Ghrelin produced?

Answer 18

Stomach

Question 19

What stimulus causes ghrelin secretion?

Answer 19

starvation

Question 20

What is the action of ghrelin?

Answer 20

strong stimulant for appetite and feeding

Question 21

Which nuclei of the hypothalamus is responsible for appetite regulation?

Answer 21

arcuate nucleus

Question 22

What hormones control appetite?

Answer 22

Leptin causes satiety (anorexigenic)
Ghrelin stimulates appetite (orexigenic)

Question 23

What is the action of the satiety and appetite centres in the hypothalamus?

Answer 23

Satiety centre:
- respond to high glucose levels
- inhibits eating
Appetite centre:
- responds to low glucose levels
- stimulates eating

Question 24

How do ghrelin and leptin regulate appetite?

Answer 24

Insulin and leptin interact with POMC in arcuate nucleus of hypothalamus to inhibit appetite
Ghrelin inhibits insulin and leptin

Question 25

What are the effects of having no leptin production/response?

Answer 25

hyperphagic - always hungry => obesity Hypothermic Infertile

Question 26

What is the effect of CCK

Answer 26

Released rapidly in response to a meal: - stimulates gallbladder contraction - secretion of pancreatic enzymes and bicarbonate - slows gastric emptying - inhibits gastric acid secretion - reduces food intake

Question 27

What are the most relevant adipose hormones?

Answer 27

Leptin Adinopectin

Question 28

What is action of adinopectin?

Answer 28

improves insulin sensitivity low in obesity and insulin resistant states

Question 29

What are the renal hormones?

Answer 29

Erythropoietin Renin Calcitriol

Question 30

What is the source, stimuli and function of erythropoietin

Answer 30

Produced by interstitial fibroblasts of kidney Response of hypoxia Promotes RBC production

Question 31

What is the source, stimuli and action of renin?

Answer 31

Produced by juxtaglomerular cells of kidney Respond to decreased arterial pressure Initiate RAAs to improve/increase blood pressure and volume

Question 32

Describe the renin-angiotensin aldosterone system

Answer 32

Question 33

what are the heart hormones/natriuretic peptides

Answer 33

BNP ANP

Question 34

What is the source of BNP?

Answer 34

ventricular cardiomyocytes

Question 35

What is the stimuli for BNP secretion?

Answer 35

stretch of ventricles caused by increased blood volume

Question 36

What is the action of BNP?

Answer 36

reduced vascular resistance (lower BP) Affects afferent and efferent glomerular arterioles to increase hydrostatic pressure and promote GFR Weakens medullary conc gradient (promote water loss) Promotes Na loss from kidney Reduces aldosterone production

Question 37

what is Zollinger-ellison syndrome and what are the clinical consequences?

Answer 37

Excess gastrin Clinical consequences: - chronic gastric ulcers due to excess gastric acid - vomiting due to stomach acidity - diarrhoea - acid secretion irritates intestines - Weight loss - dehydration - abdominal pain - inappetance - Haematemsis (vomiting blood)