This set of Molecular Endocrinology Multiple Choice Questions & Answers (MCQs) focuses on “Pancreatic and Gut Hormones – Set 2”.
1. Which among the following CCK regulates hepatic glucose production through a CNS-dependent CCKAR mechanism?
a) CCK-8
b) CCK-23
c) CCK-11
d) CCK-33
View Answer
Explanation: In response to oral nutrient intake, CCK secretion probably controls nutrient absorption and postprandial satiety. And CCK-8 regulates the production of hepatic glucose via a CNS-dependent CCKAR mechanism that may be defective in the context of insulin resistance caused by obesity.
2. Which pancreatic hormone was initially isolated from porcine intestine as a 29-amino-acid, C-terminally amidated neuropeptide?
a) Ghrelin
b) Galanin
c) Motilin
d) Amylin
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Explanation: Galanin was initially isolated as a 29-amino-acid, C-terminally amid-neuropeptide from the porcine intestine. The two molecular forms of galanin in human beings are 19 and 30 amino acids long. Galanin is found in the gut, pancreas, thyroid, and adrenal glands of the central and peripheral nervous systems, pituitary systems, and neural structures.
3. Which cells in the intestine secrete GIP, which is also called glucose-dependent insulinotropic polypeptide?
a) Pancreatic acinar cells
b) Gastroendocrine K cells
c) Enteroendocrine K cells
d) Pancreaticendocrine F cells
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Explanation: GIP, Gastro Intestinal Polypeptide is also known as glucose-dependent insulinotropic polypeptide. This hormone is secreted by the enteroendocrine K cells in the intestine. The main role of GIP is producing insulin when glucose level in the blood raises above 20%.
4. Three galanin receptor subtypes have been identified worldwide.
a) True
b) False
View Answer
Explanation: At least three subtypes of galanin receptors have been identified: GALR1, GALR2, and GALR3, which are commonly expressed in gastric and intestinal smooth muscle cells, pancreas, and CNS. The activities of galanin include food intake control, memory and cognition, and anti-nociception, and in the pituitary, pancreas, and gut, it modulates several neuroendocrine systems.
5. Galanin in humans reduces the levels of plasma insulin.
a) True
b) False
View Answer
Explanation: While galanin can inhibit transcription and insulin secretion of the proinsulin gene induced by GIP and GLP1, infusion of galanin in humans has no effect on plasma insulin levels. Galanin also prevents exocrine pancreatic secretion and the movement of intestinal ions, and it causes intestinal smooth muscle contraction and relaxation.
6. The actions of GIP on the pancreatic beta cell are primarily of which among the following peptides?
a) Inulin
b) Incretin
c) Insulin
d) Meurin
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Explanation: Incretin, a gut-derived peptide that activates insulin secretion by setting elevated plasma glucose levels after ingestion of oral nutrients, is the key action of GIP on the pancreatic beta cell. GIP receptor knockout mice are viable but, after high-fat feeding, display reduced oral glucose tolerance and increased susceptibility to diabetes.
7. Which pancreatic gut hormone is produced predominantly in G cells located in the gastric antrum and duodenal bulb?
a) Gastrin
b) Ghrelin
c) Amylin
d) Pepsin
View Answer
Explanation: Gastrin is the hormone secreted by the G-cells of gastric antrum and duodenal bulb. Many factors including the peptide and amino acid content of the gastrointestinal secretions can stimulate gastrin secretion. Large amounts of amidated gastrin are released by the foetal endocrine pancreas, indicating a possible function of gastrin in pancreatic growth.
8. Which pancreatic gut hormone induces proliferation of colon cancer cell lines expressing the CCKBR?
a) Amylin
b) Ghrelin
c) Secretin
d) Gastrin
View Answer
Explanation: Gastrin induces the proliferation of the CCKBR expressing colon cancer cell lines, but this receptor is not usually expressed by most colon cancers and normal colon epithelium. In some colon cancer cell lines, a truncated gastrin-binding receptor has been identified.
9. Which gastrin-neutralizing antisera has been shown to reduce cell proliferation and induce apoptosis in human colon cancer cells?
a) G-17
b) G-21
c) C-18
d) GC-9
View Answer
Explanation: For the possible treatment of intestinal neoplasia, the trophic effects of gastrin have led to studies of gastrin-neutralizing antisera. In comparison, G-17 has been shown to decrease cell proliferation and to induce apoptosis in CCKBR-expressing human colon cancer cells.
10. Which among the following pancreatic gut hormone is a motilin-related peptide growth hormone–releasing factor?
a) Amylin
b) Ghrelin
c) Pepsin
d) Gastrin
View Answer
Explanation: Ghrelin, a peptide associated with motilin, is a growth hormone release agent of 28 amino acids that was initially isolated from the stomach of a rat. It induces the release of growth hormone via the secretagogue receptor growth hormone (GHSR). Fasting enhances the expression of the gastric ghrelin gene, and gastric prokinetic activity is also demonstrated by ghrelin.
11. Control of ghrelin acylation is regulated by which among the following enzymes?
a) GOAT
b) JAK
c) LAC
d) POTRIK
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Explanation: Ghrelin acylation regulation is governed by ghrelin O-acyl transferase (GOAT), which is regulated by the availability of nutrients. This includes particular dietary lipids as substrates for acylation, and ties the supply of medium-chain fatty acids to the regulation of body fat mass and energy expenditure.
12. Immunoreactivity of which pancreatic gut hormone has been detected in open-type enteroendocrine epithelial M cells?
a) Motilin
b) Secretin
c) Gastrin
d) Amylin
View Answer
Explanation: Motilin exhibit immunoreactivity in the enteroendocrine epithelial M-cells. Main function of motilin is to increase the motility of migrating myoelectric complexes in the gastrointestinal secretions. It also increases the secretion of pepsin.
13. Which pancreatic gut hormone is a 13-amino-acid peptide originally detected in bovine hypothalamus?
a) Neurotensin
b) Secretin
c) Amylin
d) Motilin
View Answer
Explanation: Neurotensin was primarily discovered from the bovine hypothalamus as a 13-amino-acid peptide. Peptides like Xenin, Neuromedin N etc. are found to be neurotensin-related peptides. Its main role is in the regulation of luteinizing hormone and control of prolactin secretion.
14. Which pancreatic gut hormone stimulates pancreatic and biliary bicarbonate and water secretion?
a) Secretin
b) Somatostatin
c) Ghrelin
d) Myelin
View Answer
Explanation: Secretin promotes the secretion of pancreatic and biliary bicarbonate and water and can control the secretion of pancreatic enzymes. Secretin also facilitates pepsinogen gastric secretion and inhibits lower esophageal sphincter tone, postprandial gastric emptying, release of gastrin, and secretion of gastric acid.
15. Which pancreatic gut hormone is originally isolated as a hypothalamic growth hormone release–inhibiting factor?
a) Somatostatin
b) Secretin
c) Ghrelin
d) Motilin
View Answer
Explanation: In the intestine and pancreas, somatostatin, initially isolated as a hypothalamic growth hormone release-inhibiting factor, is also expressed. Post-translational prosomatostatin processing results in the production of somatostatin-14 and somatostatin-28, the biologically active peptides corresponding to prosomatostatin C-terminal 14 and 28 amino acids.
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