This set of Molecular Endocrinology Multiple Choice Questions & Answers (MCQs) focuses on “Pancreatic and Gut Hormones”.
1. Which pancreatic hormone is also known as islet amyloid associated peptide?
a) Amylin
b) Pepsin
c) Leptin
d) Insulin
View Answer
Explanation: Amylin is a hormone produced in islet beta cells. This hormone is scattered in endocrine cells in the stomach and in the proximal small intestine. Hence, this hormone is otherwise known as islet amyloid-associated peptide. In rodents and humans, exogenous administration of amylin prevents gastric emptying and glucagon secretion.
2. Amylin exerts its physiologic actions through interaction with the calcitonin receptor in the presence of which among the following protein?
a) RFLP
b) RAMP
c) RALP
d) SERP
View Answer
Explanation: In the presence of a receptor activity-modifying protein, Amylin exerts its physiological actions by interaction with the calcitonin receptor (RAMP). Mice deficient in amylin exhibit mild islet function disruptions and increased glucose clearance following a glucose challenge.
3. Which among the following is an analogue for the pancreatic hormone amylin?
a) Pregnenolone
b) Exenatide
c) Pramlintide
d) Toxicanin
View Answer
Explanation: In human physiology, the function of gut-derived amylin has not been clearly identified, but the amylin analogue pramlintide is approved for the adjunctive treatment of type 1 and type 2 diabetes with co-administration of insulin. It delays gastric emptying by vagally-mediated pathways in a dose-dependent manner.
4. The system of apelin shares essential similarities with the renin-angiotensin mechanism.
a) True
b) False
View Answer
Explanation: Important similarities with the renin-angiotensin system are shared by the apelin system and the two systems may have antagonistic and overlapping functions. In left ventricular dysfunction, Apelin is downregulated and, in mouse models of insulin resistance, increases insulin action.
5. In vitro, the apelin receptor serves as a coreceptor for the human immunodeficiency virus (HIV).
a) True
b) False
View Answer
Explanation: In left ventricular dysfunction, Apelin is downregulated, is an adipokine, and improves insulin action in mouse insulin resistance models. The apelin receptor acts in vitro as a coreceptor for human immunodeficiency virus (HIV) and the peptides associated with apelin serve as HIV infection antagonists.
6. Which is the endogenous ligand for the orphan G protein–coupled receptor APJ?
a) Amylin
b) Apelin
c) Pepsin
d) Casin
View Answer
Explanation: Apelin is a 36-amino acid peptide originally isolated from bovine stomach extracts that has been determined to be the orphan G protein-coupled APJ receptor endogenous ligand (now designated APLNR). In peripheral tissues, such as the lung, heart, and mammary gland, apelin and its receptor are commonly expressed, with apelin most abundant in the stomach.
7. In humans, which genes encode calcitonin and CGRP?
a) CALCA and CALCB
b) CALCD and CALC9
c) AMAL6 and AMAL9
d) CALC6 and CGR8
View Answer
Explanation: The gene-related peptide (CGRP) of calcitonin is part of a broader peptide family that includes calcitonin, amylin, and adrenomedullin. In humans, separate CALCA and CALCB genes encode calcitonin and CGRP and give rise to two α-CGRP and β-CGRP labelled 37-amino-acid, carboxy terminal-amidated neuropeptides.
8. The neuropeptide alpha-CGRP produced by the genes CALCA and CALCB is primarily expressed in which neurons?
a) Efferent sensory neurons
b) Afferent motor neurons
c) Enteric neurons
d) Afferent sensory neurons
View Answer
Explanation: The neuropeptides produced by the genes CALCA and CALCB share a significant homology of the amino acid series, with a difference in humans of only three amino acids. Alpha-CGRP is primarily expressed in primary afferent sensory neurons that originate from the spinal cord.
9. The neuropeptide beta-CGRP produced by the genes CALCA and CALCB is primarily expressed in which neurons?
a) Enteric neurons
b) Efferent sensory neurons
c) Afferent motor neurons
d) Afferent sensory neurons
View Answer
Explanation: The neuropeptides formed by the genes CALCA and CALCB share an essential homology of the amino acid sequence, with a difference of just three amino acids in humans. β-CGRP is expressed predominantly in enteric neurons. β-CGRP is expressed predominantly in enteric neurons and is a 37-amino acid neuropeptide.
10. Co-expression of calcitonin receptor–like receptor with RAMP1 results in which among the following conditions?
a) Specificity for adrenomedullin
b) Ligand specificity for CGRP
c) Specificity for Calcitonin
d) Specificity for Endocrine signals
View Answer
Explanation: A family of RAMPs interacts with two calcitonin/CGRP seven transmembrane domain, G protein-coupled receptors. Calcitonin-like receptor co-expression with RAMP1 results in the specificity of CGRP ligands.
11. CGRP immunoreactivity has been localized to which cells in the small intestine?
a) Endocrine cells and neurons
b) Endocrine cells
c) Acinar Cells and neurons
d) Acinar cells
View Answer
Explanation: Enteroendocrine cells in the human rectum and endocrine cells and neurons in the small intestine have been localized to CGRP immunoreactivity. In response to glucose and via gastric acid secretion, intestinal CGRP is released.
12. Which hormone was first characterized as a factor that stimulates gallbladder contraction?
a) Cholecystokinin
b) Apelin
c) Amylin
d) Ghrelin
View Answer
Explanation: CCK is the hormone that induces contraction of the gallbladder. CCK is the hormone used for fat and protein digestion. It contracts the gall bladder muscles and relaxes the Sphincter of Oddi for the transfer of bile from gall bladder to duodenum.
13. Which among the following is a major active form of the prohormone produced by CCK?
a) CCK-8
b) CCK-22
c) CCK-83
d) CCK-5
View Answer
Explanation: The CCK gene encodes a prohormone of 94 amino acids that is post-translationally translated into multiple molecular forms in a tissue-specific fashion, including CCK-83, CCK-58, CCK-39, CCK-33, CCK-22, CCK-8, and CCK-5, all sharing a similar C-terminus. The key active form, CCK-8, is an octapeptide containing a trace of sulphated tyrosine and amidated tyrosine.
14. Which among the following prohormones of CCK act as the major circular form in humans?
a) CCK-33
b) CCK-58
c) CCK-83
d) CCK-39
View Answer
Explanation: CCK genes produce different prohormones, all sharing a similar C terminus. They are CCK-83, CCK-58, CCK-39, CCK-33, CCK-22, CCK-8, and CCK-5. The predominant circular form in human plasma seems to be CCK-33.
15. CCK binds with high affinity to which among the following G protein–coupled receptor?
a) CCKAR
b) CCFRG
c) CCGAL
d) CCADB
View Answer
Explanation: CCK binds to CCKAR, a seven transmembrane domain, G protein-coupled receptor expressed in pancreatic acinar cells, gallbladder, smooth muscle, gastric mucosa chief and D cells, and central and peripheral nervous systems, with high affinity. In the stomach, while increasing the force of antral and pyloric contractions, CCK inhibits proximal gastric motility.
Sanfoundry Global Education & Learning Series – Molecular Endocrinology.
To practice all areas of Molecular Endocrinology, here is complete set of 1000+ Multiple Choice Questions and Answers.
If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]
