Endocrinology Practice Questions

Q: Which of the following is called hunger hormone?

Ghrelin. ***Ghrelin*** - **Ghrelin** is often referred to as the **"hunger hormone"** because it stimulates appetite, increases food intake, and promotes fat storage. - It is primarily produced in the **stomach** and its levels rise before meals and decrease after meals. *Insulin* - **Insulin** is a hormone primarily involved in regulating **blood glucose levels** by facilitating glucose uptake into cells. - It does not directly induce hunger but rather signals satiety and energy storage. *Leptin* - **Leptin** is known as the **"satiety hormone"** because it suppresses appetite and signals to the brain that the body has sufficient energy stores. - It is produced by **adipose tissue** (fat cells) and helps regulate long-term energy balance. *Cortisol* - **Cortisol** is a **stress hormone** involved in the body's 'fight or flight' response, influencing metabolism, immune function, and inflammation. - While chronic stress and elevated cortisol can indirectly affect appetite and food cravings, it is not primarily known as a hunger or satiety hormone.

Q: Growth hormone secretion is decreased by

Glucose. ***Glucose*** - **High blood glucose levels** act as a negative feedback signal to the **hypothalamus** and **anterior pituitary**, inhibiting the release of Growth Hormone-Releasing Hormone (GHRH) and Growth Hormone (GH), respectively. - This physiological response helps to prevent excessive growth and metabolism when energy substrates are readily available. *Exercise* - **Physical exercise**, particularly intense activity, is a powerful stimulus for **GH secretion**, likely due to increased sympathetic activity and changes in circulating metabolites. - This GH surge during exercise contributes to **fat mobilization** and **muscle protein synthesis**. *Stress* - Both **physical and psychological stress** can significantly stimulate **GH release**, mediated by increased activity of the **hypothalamic-pituitary-adrenal (HPA) axis** and adrenaline. - GH's role here is to mobilize energy resources to cope with the stressful situation. *Glucagon* - **Glucagon**, a hormone primarily known for raising blood glucose, also has a direct stimulatory effect on **GH secretion**, especially during periods of low glucose or fasting. - This effect is utilized in certain diagnostic tests for GH deficiency.

Q: A shift to the right in the biological activity dose- response curve for a hormone with no accompanying change in the maximal response indicates:

Decreased sensitivity. ***Decreased sensitivity*** - A **right shift** in the dose-response curve means a **higher concentration** of the hormone is required to achieve the same effect, indicating reduced sensitivity. - No change in the **maximal response** implies the system can still reach the same peak effect, but it needs more hormone. *Increased sensitivity and decreased responsiveness* - **Increased sensitivity** would be represented by a **left shift** in the dose-response curve, meaning less hormone is needed for a given effect. - **Decreased responsiveness** implies a reduction in the **maximal effect**, which is stated as unchanged in the question. *Increased responsiveness* - **Increased responsiveness** would mean a **higher maximal effect** can be achieved or a steeper slope in the dose-response curve, neither of which is described. - A right shift is related to the dose required for an effect, not the magnitude of the maximal effect. *Decreased responsiveness and decreased sensitivity* - While **decreased sensitivity** is correct, **decreased responsiveness** is incorrect because the question specifies "no accompanying change in the maximal response." - **Decreased responsiveness** would be indicated by a **lower maximal effect (Emax)**, which is not the case here.

Q: Estrogen administration in a menopausal woman increases the:

Bone mass. ***Bone mass*** - Estrogen plays a crucial role in maintaining **bone density** by inhibiting osteoclast activity and promoting osteoblast function. - In menopausal women, estrogen administration counteracts bone loss and thus **increases bone mass**, reducing the risk of osteoporosis. *Gonadotropin secretion* - In menopausal women, **gonadotropin-releasing hormone (GnRH)** and subsequent **FSH and LH levels are elevated** due to the absence of ovarian estrogen feedback. - Estrogen administration would exert a **negative feedback** on the hypothalamus and pituitary, thereby **decreasing**, not increasing, gonadotropin secretion. *Muscle mass* - While estrogen has some anabolic effects, **androgens** (like testosterone) are the primary hormones responsible for significantly increasing muscle mass. - Estrogen administration to menopausal women is not a primary intervention for increasing muscle mass; its effects on this parameter are generally **modest or negligible**. *LDL cholesterol* - Estrogen generally has a **favorable effect on lipid profiles**, typically leading to a **decrease in LDL cholesterol** and an increase in HDL cholesterol. - Therefore, estrogen administration would generally **reduce**, not increase, LDL cholesterol levels.

Q: Which among the following is the function of ghrelin?

Stimulation of appetite. ***Stimulation of appetite*** - **Ghrelin** is often referred to as the **"hunger hormone"** because its primary function is to stimulate appetite. - Levels of ghrelin typically rise before meals and decrease after eating, signaling the brain to initiate food intake. *Suppression of appetite* - Hormones like **leptin** and **cholecystokinin (CCK)** are known to suppress appetite, acting as satiety signals. - Ghrelin has the opposite effect, promoting feelings of hunger rather than fullness. *Stimulation of sleep* - While ghrelin levels can influence **sleep-wake cycles** through its effects on the **hypothalamus**, its primary and most direct function is not the stimulation of sleep. - Sleep regulation is a complex process involving multiple neurotransmitters and hormones distinct from ghrelin's main role in hunger. *Regulation of gastric motility* - Although ghrelin can have some effects on **gastrointestinal motility**, its main function is not to regulate it. - Gastric motility is primarily influenced by hormones like **motilin** and the **enteric nervous system**.

Q: Which of the following has growth hormone stimulating activity?

Ghrelin. **Ghrelin** - Ghrelin is a **peptide hormone** primarily produced in the stomach, often referred to as the "**hunger hormone**." - It directly stimulates the secretion of **growth hormone (GH)** from the anterior pituitary gland, acting as a natural **growth hormone secretagogue**. *REM sleep* - While a significant portion of **growth hormone (GH) secretion** occurs during sleep, it is predominantly associated with **slow-wave sleep (NREM stage 3 and 4)** rather than REM sleep. - REM sleep is primarily characterized by dreaming and muscle atonia, with less direct correlation to GH pulsatility. *IGF-1* - **Insulin-like growth factor 1 (IGF-1)** is a hormone primarily produced in the liver in response to growth hormone (GH). - IGF-1 actually exerts **negative feedback** on GH secretion, inhibiting its release rather than stimulating it. *Somatostatin* - **Somatostatin** is a peptide hormone produced in various tissues, including the hypothalamus and pancreas. - It acts as a **potent inhibitor** of growth hormone (GH) secretion from the anterior pituitary gland.

Q: Major hormone secreted by zona reticularis of adrenal cortex?

Androgens. ***Androgens*** - The **zona reticularis** is the innermost layer of the adrenal cortex and is primarily responsible for the production of **adrenal androgens**, such as dehydroepiandrosterone (DHEA) and androstenedione. - These androgens contribute to secondary sexual characteristics, particularly in females, and can be converted to more potent androgens or estrogens in peripheral tissues. *Aldosterone* - **Aldosterone** is the primary **mineralocorticoid** and is secreted by the outermost layer of the adrenal cortex, the **zona glomerulosa**. - Its main role is to regulate **sodium and potassium balance** and **blood pressure** through its effects on the kidneys. *Glucocorticoids* - **Glucocorticoids**, with **cortisol** being the main one, are secreted by the middle layer of the adrenal cortex, the **zona fasciculata**. - They are involved in **glucose metabolism**, stress response, and immune system modulation. *Mineralocorticoids* - While androgens are steroid hormones, the term **mineralocorticoids** refers specifically to hormones like **aldosterone**, which are produced in the **zona glomerulosa**. - Their primary function is to regulate mineral balance, distinct from the sex hormone activity of androgens.

Q: Hypothalamus increases release of all hormones from the pituitary except ?

Prolactin. ***Prolactin*** - The hypothalamus primarily **inhibits prolactin release** from the anterior pituitary via **dopamine** (prolactin-inhibiting hormone). - All other hormones listed (ACTH, TSH, FSH/LH, GH) are stimulated by their respective hypothalamic releasing hormones. *ACTH* - The hypothalamus **increases ACTH release** by secreting **corticotropin-releasing hormone (CRH)**, which acts on the anterior pituitary. - CRH stimulates corticotrophs to synthesize and release ACTH, which then acts on the adrenal glands. *TSH* - The hypothalamus **increases TSH release** by secreting **thyrotropin-releasing hormone (TRH)**, which stimulates thyrotrophs in the anterior pituitary. - TRH also has a minor stimulatory effect on prolactin release, but its primary role is TSH stimulation. *FSH* - The hypothalamus **increases FSH release** (along with LH) by secreting **gonadotropin-releasing hormone (GnRH)** in a pulsatile manner. - GnRH stimulates gonadotrophs in the anterior pituitary to produce and secrete both FSH and LH.

Q: Calcium absorption is increased by

1.25 Dihydrocholecalciferol. ***1.25 Dihydrocholecalciferol*** - **1,25-dihydroxycholecalciferol** (calcitriol), the active form of vitamin D, plays a crucial role in **calcium homeostasis** by enhancing calcium absorption from the intestine. - This hormone stimulates the synthesis of **calcium-binding proteins** in intestinal epithelial cells, facilitating the uptake and transport of dietary calcium. *Hypercalcemia* - **Hypercalcemia** (high blood calcium levels) **inhibits** the production of parathyroid hormone (PTH) and **reduces the activation of vitamin D**, thereby decreasing calcium absorption. - The body aims to maintain calcium balance, so excessive calcium in the blood would trigger mechanisms to reduce further absorption, not increase it. *Oxalates in the diet* - **Oxalates** (found in foods like spinach and rhubarb) bind to calcium in the gut to form **insoluble calcium oxalate**, which cannot be absorbed. - This binding effectively **reduces the bioavailability** of dietary calcium, making it less available for absorption. *Iron overload* - **Iron overload** primarily affects iron metabolism and storage, with limited direct impact on calcium absorption mechanisms. - While excessive iron can have systemic effects, it does not directly enhance the absorption of calcium from the intestine.

Q: What is the effect of inhibin B hormone?

Inhibits FSH secretion from anterior pituitary. ***Inhibits FSH secretion from anterior pituitary*** - **Inhibin B** is a hormone produced by the **Sertoli cells** in males and **granulosa cells** in females. - Its primary function is to provide **negative feedback** to the anterior pituitary, specifically **inhibiting the release of follicle-stimulating hormone (FSH)**. *Stimulates Sertoli cell proliferation* - **FSH** (not inhibin B) is responsible for stimulating **Sertoli cell proliferation** and differentiation. - **Inhibin B** is produced by mature Sertoli cells, indicating their functional status rather than promoting their growth. *Directly stimulates seminiferous tubule development* - **FSH** and **testosterone** are the primary hormones crucial for the development and maintenance of the **seminiferous tubules**. - **Inhibin B** acts indirectly by regulating FSH, but it does not directly stimulate tubule development. *Directly enhances spermatogenesis rate* - While **inhibin B** production is correlated with the rate of spermatogenesis (it's high when spermatogenesis is active), it does not directly enhance the process. - **FSH** and **testosterone** are the direct hormonal regulators that enhance the rate of **spermatogenesis**.

Question 1

Which of the following is called hunger hormone?

Accepted Answer

Ghrelin

Answer

Insulin

Answer

Leptin

Answer

Cortisol

Question 2

Growth hormone secretion is decreased by

Accepted Answer

Glucose

Answer

Exercise

Answer

Stress

Answer

Glucagon

Question 3

A shift to the right in the biological activity dose- response curve for a hormone with no accompanying change in the maximal response indicates:

Accepted Answer

Decreased sensitivity

Answer

Increased sensitivity and decreased responsiveness

Answer

Increased responsiveness

Answer

Decreased responsiveness and decreased sensitivity

Question 4

Estrogen administration in a menopausal woman increases the:

Accepted Answer

Bone mass

Answer

Gonadotropin secretion

Answer

Muscle mass

Answer

LDL cholesterol

Question 5

Which among the following is the function of ghrelin?

Accepted Answer

Stimulation of appetite

Answer

Suppression of appetite

Answer

Stimulation of sleep

Answer

Regulation of gastric motility

Question 6

Which of the following has growth hormone stimulating activity?

Accepted Answer

Ghrelin

Answer

REM sleep

Answer

IGF-1

Answer

Somatostatin

Question 7

Major hormone secreted by zona reticularis of adrenal cortex?

Accepted Answer

Androgens

Answer

Aldosterone

Answer

Glucocorticoids

Answer

Mineralocorticoids

Question 8

Hypothalamus increases release of all hormones from the pituitary except ?

Accepted Answer

Prolactin

Answer

ACTH

Answer

TSH

Answer

FSH

Question 9

Calcium absorption is increased by

Accepted Answer

1.25 Dihydrocholecalciferol

Answer

Hypercalcemia

Answer

Oxalates in the diet

Answer

Iron overload

Question 10

What is the effect of inhibin B hormone?

Accepted Answer

Inhibits FSH secretion from anterior pituitary

Answer

Stimulates Sertoli cell proliferation

Answer

Directly stimulates seminiferous tubule development

Answer

Directly enhances spermatogenesis rate

Endocrinology — MCQs

Endocrinology — MCQs

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