Multiple Choice Questions on Pituitary Hormones & Disorders

Multiple Choice Questions on Pituitary Hormones & Disorders

1) Release of Anterior Pituitary hormones is regulated by the hormones secreted from the hypothalamus. 

Which of the following hormone is not released from the hypothalamus?
a) Growth hormone-releasing hormone
b) Thyroid Stimulating hormone
c) Gonadotropin-releasing hormone
d) Corticotrophin-releasing hormone

2) Thyroid-stimulating hormone (TSH), luteinizing hormone (LH), and Follicular stimulating hormone (FSH) are the hormones released from the anterior pituitary gland. 

Which of the following is not a correct statement regarding these hormones?
a) They belong to the glycoprotein family
b) Each has alpha and beta subunits.
c) The alpha subunits are identical
d) The beta subunits are identical

3) Proopopmelanocorticotropin (POMC) is a precursor for the following peptides, EXCEPT:
a) Adrenocorticotropic hormone (ACTH)
b) Thyroid Stimulating hormone (TSH)
c) Beta-lipotropin
d) Beta-endorphin

4) The growth hormone is synthesized by the anterior pituitary gland, and released into the circulation in a pulsatile manner. 

Which of the following statement is true regarding growth hormones?
a) Secretion is decreased by sleep and physiological stress
b) Secretion is decreased by somatostatin & somatomedins
c) Growth hormone negatively regulates the secretion of Insulin-like growth factors
d) Growth hormone acts via the G protein receptor family

5) The growth hormone binds to its cell surface receptor and activates the.......................................?
a) cGMP production
b) cAMP production
c) Tyrosine kinase activity
d) Calcium and Diacylglycerol

6) The metabolic action of growth hormones includes the following, Except?
a) Increased glucose uptake into cells
b) Increased Lipolysis
c) Increased protein synthesis
d) Increased Bone Growth

7) Which of the following conditions do not manifest as short stature?
a) Hyposecretion of Growth hormone-releasing hormone
b) Failure to generate IGF in the liver
c) Growth hormone receptor deficiency
d) Hypersecretion of Growth hormone-releasing hormone

8) The condition associated with the onset of hypersecretion of growth hormone in adults is known as
a) Gigantism
b) Dwarfism
c) Acromegaly
d) None of the above

9) Which of the following hormone originates from the anterior pituitary?
a) Dopamine
b) Growth hormone-releasing hormone
c) Gonadotropin-releasing hormone (GnRH)
d) Thyroid-stimulating hormone (TSH)

10) A 50-years old man has "puffy" skin and is lethargic. His plasma TSH level is low and increased markedly when he is given Thyrotropin-releasing hormone. 

What is the likely cause?
a) Hyperthyroidism due to a thyroid tumor
b) Hyperthyroidism due to an abnormality in the hypothalamus
c) Hypothyroidism due to an abnormality in the thyroid
d) Hypothyroidism due to an abnormality in the hypothalamus

11) Which of the following increases the secretion of growth hormone?
a) Insulin-like growth factor-1
b) Somatostatin
c) Hypoglycemia
d) Exogenous GH administration

12) Prolactin is structurally homologous to growth hormones and is responsible for lactogenesis. 

Which of the following factors increases prolactin secretion?
a) Dopamine
b) Bromocriptine
c) Somatostatin
d) Thyrotrophin-releasing hormone

13) Prolactin is structurally homologous to growth hormones and is responsible for lactogenesis. 

Which of the following factors decreases prolactin secretion?
a) Estrogen
b) Sleep
c) Thyrotrophin-releasing hormone
d) Dopamine

14) All the following statements are correct regarding the hyperprolactinemia ( prolactin excess) EXCEPT:
a) It results from hypothalamic destruction  or prolactin-secreting tumors
b) It causes galactorrhea and decreased libido
c) It causes failure to ovulate and amenorrhea by inhibiting GnRH
d) Increased Domaine secretion

15) Which of the following hormones is synthesized by the posterior pituitary gland?
a) LH & FSH
b) TSH
c) Antidiuretic hormone and Oxytocin
d) Growth hormone and Prolactin

16) The antidiuretic hormone (ADH) originates primarily in the supraoptic nuclei of the hypothalamus. Which of the following statement is FALSE regarding ADH?
a) ADH regulates serum osmolality by increasing the water permeability in the distal tubules and collecting ducts
b) ADH increases vascular smooth muscles
c) ADH secretion is decreased by arterial natriuretic peptide
d) ADH increases water reabsorption in proximal tubules

17) Oxytocin originates primarily in the paraventricular nuclei of the hypothalamus. 

Which of the following statement is FALSE regarding oxytocin?
a) Suckling is the major stimulus for oxytocin secretion
b) Dilation of the cervix and orgasm increases oxytocin
c) Oxytocin causes contraction of the uterus
d) None of the above


Multiple Choice Question Answer:
1- b) Thyroid Stimulating hormone

The key hormones produced by the hypothalamus are: 

Gonadotropin-Releasing Hormone (GnRH): GnRH stimulates the anterior pituitary to release two important reproductive hormones: luteinizing hormone (LH) and follicle-stimulating hormone (FSH). These hormones are involved in regulating the menstrual cycle, ovulation, and the production of sex hormones (estrogen and progesterone in females, and testosterone in males).

Thyrotropin-Releasing Hormone (TRH): TRH stimulates the anterior pituitary to release thyroid-stimulating hormone (TSH). TSH, in turn, stimulates the thyroid gland to produce and release thyroid hormones (thyroxine, T4, and triiodothyronine, T3), which play a crucial role in regulating metabolism and energy levels.

Corticotropin-Releasing Hormone (CRH): CRH stimulates the anterior pituitary to release adrenocorticotropic hormone (ACTH). ACTH then stimulates the adrenal glands to release cortisol, a stress hormone that helps regulate metabolism, immune responses, and the body's response to stress.

Growth Hormone-Releasing Hormone (GHRH): GHRH stimulates the anterior pituitary to release growth hormone (GH). GH plays a role in growth, cell reproduction, and regeneration, as well as regulating metabolism.

Somatostatin (Growth Hormone-Inhibiting Hormone): Somatostatin inhibits the release of growth hormone (GH) from the anterior pituitary. It also has inhibitory effects on other hormones, such as insulin and glucagon, which regulate blood sugar levels.

Prolactin-Releasing Hormone (PRH) and Prolactin-Inhibiting Hormone (PIH, also called Dopamine): The hypothalamus produces both PRH and PIH. PIH, which is primarily dopamine, inhibits the release of prolactin, a hormone that stimulates milk production in lactating individuals.

2-d) The beta subunits are identical

Thyroid-Stimulating Hormone (TSH), Luteinizing Hormone (LH), and Follicle-Stimulating Hormone (FSH) are all glycoprotein hormones, meaning they are composed of two subunits: an alpha subunit and a beta subunit. The alpha subunit is common among all three hormones, while the beta subunit is specific to each hormone. This common alpha subunit is shared with other glycoprotein hormones as well.

3-b) TSH

The notable peptides produced from POMC include:

Adrenocorticotropic Hormone (ACTH): This hormone is involved in the regulation of the adrenal glands. It stimulates the adrenal cortex to produce and release cortisol, which is important for regulating metabolism, immune responses, and the body's response to stress.

Beta-Endorphin: Beta-endorphin is an endogenous opioid peptide that plays a role in pain modulation and mood regulation. It is associated with feelings of euphoria and is released in response to stress and pain.

Melanocyte-Stimulating Hormones (MSHs): POMC gives rise to various forms of MSHs, including alpha-melanocyte-stimulating hormone (α-MSH) and others. MSHs play a role in regulating pigmentation in the skin, as well as influencing appetite and energy balance.

Corticotropin-Like Intermediate Peptide (CLIP): CLIP is a peptide fragment that is formed during the processing of POMC. Its exact biological function is not fully understood, but it may have roles in immune modulation and inflammation.

4-b) Secretion is decreased by somatostatin & somatomedins

Growth hormone (GH) secretion is regulated by a complex interplay of factors, and somatostatin and somatomedins are both involved in inhibiting GH secretion.

Somatostatin: Also known as growth hormone-inhibiting hormone (GHIH), somatostatin is produced by the hypothalamus and inhibits the release of growth hormone from the anterior pituitary gland. This hormone acts as a negative regulator of GH secretion.

Somatomedins (Insulin-like Growth Factors - IGFs): Somatomedins, particularly insulin-like growth factor 1 (IGF-1), are produced in response to growth hormone stimulation. They are released from the liver and other tissues in response to GH and play a key role in mediating many of the growth-promoting effects of GH. However, IGF-1 also feeds back to the hypothalamus and anterior pituitary to inhibit further GH release, acting as a negative regulator.

Regarding the other options:

a) Secretion is decreased by sleep and physiological stress: This statement is not entirely accurate. GH secretion is actually increased during deep sleep, particularly during the first hours of sleep. Additionally, physiological stress, such as exercise, can stimulate GH release.

c) Growth hormone negatively regulates the secretion of Insulin-like growth factors: This statement is incorrect. Growth hormone stimulates the secretion of insulin-like growth factors (IGFs), particularly IGF-1, which mediates many of the growth-promoting effects of GH.

d) Growth hormone acts via the G protein receptor family explain: This statement is not true. While growth hormone does exert its effects through receptor binding, it does not primarily act via the G protein-coupled receptor family. Instead, growth hormone receptors belong to a distinct receptor family called the cytokine receptor superfamily.

5-c) Tyrosine kinase activity

Steps for activation of Tyrosine kinase activity

Binding of Growth Hormone (GH): Growth hormone is a peptide hormone secreted by the anterior pituitary gland in response to signals from the hypothalamus. It circulates in the bloodstream and binds to its specific receptor, known as the growth hormone receptor (GHR), which is expressed on the surface of target cells.

GHR Dimerization: The binding of growth hormone to one GHR molecule induces conformational changes in the receptor that allow it to form a dimer with another GHR molecule. This dimerization brings together the intracellular domains of the receptors, creating a signaling complex.

Activation of JAK-STAT Pathway: Once the GHR dimer is formed, it activates a class of enzymes known as Janus kinases (JAKs), which are associated with the intracellular domains of the receptor. JAKs phosphorylate tyrosine residues on the GHR and also on specific tyrosine residues of signal transducer and activator of transcription (STAT) proteins.

STAT Activation and Translocation: Phosphorylated STAT proteins form dimers and translocate from the cytoplasm into the nucleus. In the nucleus, they bind to specific DNA sequences known as promoter elements, which regulate the transcription of target genes.

6-a) Increased glucose uptake into cells

Growth hormone (GH) can influence glucose metabolism by decreasing glucose uptake into cells, particularly muscle cells. This action helps to conserve glucose for other tissues, such as the brain, during periods of fasting or stress. 

7-d) Hypersecretion of Growth hormone-releasing hormone

8-c) Acromegaly
9-d) Thyroid-stimulating hormone (TSH)
10-b) Hyperthyroidism due to an abnormality in the hypothalamus
11-c) Hypoglycemia
13-d) Thyrotrophin-releasing hormone
14-d) Increased Domaine secretion
15-c) Antidiuretic hormone and oxytocin
16-d) ADH increases water reabsorption in proximal tubules
17-d) None of the above