This set of Molecular Endocrinology Multiple Choice Questions & Answers (MCQs) focuses on “Hormones of Middle and Posterior Pituitary Lobe”.
1. Which hormones are otherwise known as melanocyte stimulating hormones?
a) Hormones of the middle lobe of pituitary
b) Hormones of the anterior lobe of pituitary
c) Hormones of the posterior lobe of pituitary
d) Pituitary tropic hormones
View Answer
Explanation: The hormones secreted by the pituitary gland’s intermediate lobe or middle lobe are called melanocyte-stimulating hormones or MSH. POMC is the precursor molecule that supplies ACTH and beta-lipotropin by the cleavage of proteases.
2. Which pituitary hormone is involved in skin pigmentation?
a) FSH
b) MSH
c) LH
d) TSH
View Answer
Explanation: MSH (melanocyte-stimulating hormones) darkens the skin and is active in the pigmentation of the skin by melanin secretion with the help of melanocytes. This hormone is produced from the middle lobe of the pituitary gland.
3. Which among the following is an example of the hormone released from the posterior pituitary lobe?
a) FSH
b) LH
c) Oxytocin
d) MSH
View Answer
Explanation: Oxytocin and Vasopressin are the hormones released from the posterior pituitary lobe. They are both small peptides and contain nine amino acids. Oxytocin is a hormone that serves as a chemical messenger in the brain and acts on organs in the body (including the breast and uterus), regulating key aspects of the reproductive system, including childbirth and lactation, and aspects of human behavior.
4. In nephrogenic diabetes insipidus, due to renal injury, the kidneys cannot respond to vasopressin.
a) True
b) False
View Answer
Explanation: In the case of nephrogenic diabetes insipidus, due to renal injury, the kidneys cannot respond to vasopressin. In psychiatric patients taking lithium treatment, this damage is usually normal. Nephrogenic diabetes insipidus (NDI) is an inability to concentrate urine due to impaired vasopressin reaction of the renal tubule (ADH), leading to the excretion of significant quantities of dilute urine.
5. Smooth muscle contraction is the main feature of oxytocin.
a) True
b) False
View Answer
Explanation: Smooth muscle contraction is oxytocin’s primary function. There are actually two effects, one called the galactobolic effect on mammary glands and the other called the uterine effect on the uterus.
6. Which neurons act as the secretory site in posterior pituitary lobe?
a) Unipolar neuron
b) Neurosecretory neuron
c) bipolar neurons
d) Motor neurons
View Answer
Explanation: Posterior pituitary hormones are produced in neurosecretory neurons. In the pituitary, they are stored in combination with neurophysin I and II proteins with molecular weights of 19000 and 21000 respectively. The release of these two hormones is distinct from one another.
7. Which pituitary hormone carry out antidiuretic action?
a) Vasopressin
b) Oxytocin
c) TSH
d) FSH
View Answer
Explanation: Antidiuretic effect is the main function of vasopressin hormone. The distal tubules and collecting ducts reabsorb water from the kidneys with the help of this hormone. Vasopressin (arginine vasopressin, AVP; antidiuretic hormone, ADH) is a hormone peptide formed in the hypothalamus that is then transported to the posterior pituitary via axons, which releases it into the blood.
8. Which among the following is an example of the drug that inhibits antidiuretic action of vasopressin?
a) Zintec
b) Proxivan
c) Ibufren
d) Halothane
View Answer
Explanation: The antidiuretic activity of vasopressin is blocked by halothane, colchicine, and vinblastine. The antidiuretic effect contributes to low volume and elevated amounts of hypertonic urine. Halothane, which was introduced into the clinical practice of anesthesia in 1956, is a volatile general anesthetic.
9. What is the name of the disease caused by the deficiency of vasopressin?
a) Diabetes insipidus
b) Diabetes mellitus
c) Gout
d) Phenylketonuria
View Answer
Explanation: Diabetes insipidus is the disease caused as a result of failure of vasopressin secretion or action. It is distinguished by very high urinary production levels, with low specific gravity and extreme thirst.
10. Which among the following is an example of galactobolic effect of oxytocin?
a) Walking
b) Sucking of nipples
c) Parturition
d) Micturition
View Answer
Explanation: Galactobolic effect is triggered by a neuroendocrinal reflex, such as nipple suckling. When doing so, it allows the myoepithelial cells surrounding mammary alveoli to contract. Sensory signals travel from the nipple to the brain while a baby suckles at the breast.
11. Which female hormone increases the oxytocin receptors during pregnancy?
a) Progesterone
b) FSH
c) LH
d) Estrogen
View Answer
Explanation: During pregnancy, estrogen increases the number of oxytocin receptors. Whereas progesterone, reduces it and also prevents oxytocin secretion. In pregnancy times, levels of oestrogen rise gradually and hit their peak in the third trimester.
12. Which pituitary hormone is secreted during coitus that promote semen aspiration in females?
a) Oxytocin
b) Vasopressin
c) FSH
d) LH
View Answer
Explanation: Oxytocin is also secreted by the female uterus during coitus, facilitating the migration of sperm into the uterus. This is improved by the increase of menstrual cycle estrogen in the follicular process.
13. Which pituitary hormone increases the permeability of urea in collecting ducts?
a) Oxytocin
b) Vasopressin
c) FSH
d) LH
View Answer
Explanation: Vasopressin improves the permeability of medullary collecting ducts to urea. This leads to urea retention and ultimately contributes to medullary interstitial hypertonicity. Phloretin can counteract the retention effect of urea.
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]
