Endocrine Pharmacology — MCQs

Endocrine Pharmacology Indian Medical PG Practice Questions and MCQs

Question 761: Which of the following compounds has been studied as a potential male contraceptive?

A. Quinesterol
B. Saheli
C. MALA - N
D. Gossypol (Correct Answer)

Explanation: ***Gossypol*** - **Gossypol** is a natural compound derived from cotton plants that has been extensively studied for its **male contraceptive** properties due to its effect on sperm production. - Research has shown that gossypol inhibits **spermatogenesis** by affecting various enzymes and processes within the testes, leading to reduced sperm count and motility. However, its use has been limited due to concerns about potential side effects, including **hypokalemia** and irreversible infertility in some individuals. *Quinesterol* - **Quinesterol** is a **synthetic estrogen** primarily used as a component of oral contraceptives for women. - Its mechanism of action involves suppressing ovulation and altering the endometrial lining, making it unsuitable as a male contraceptive. *Saheli* - **Saheli**, also known as Centchroman or Ormeloxifene, is a **non-steroidal oral contraceptive** developed in India and is used for women. - It acts as a **selective estrogen receptor modulator (SERM)** in the uterus, preventing implantation, and is not designed or effective for male contraception. *MALA-N* - **MALA-N** (Norethisterone enanthate or NET-EN) is a **long-acting injectable progestogen contraceptive** used for women in India. - It works by suppressing ovulation, thickening cervical mucus, and altering the endometrium, making it unsuitable for male contraception.

Question 762: What is the longest-acting insulin?

A. Insulin-zinc suspension
B. Protamine-zinc insulin
C. Degludec insulin (Correct Answer)
D. Neutral protamine Hagedorn (NPH)

Explanation: ***Degludec insulin*** - Degludec insulin is an **ultra-long-acting insulin analog**, providing a duration of action of up to 42 hours, making it the longest-acting available. - Its prolonged action is due to the formation of soluble **multihexamers** in the subcutaneous tissue, which slowly release insulin monomers into the circulation. *Insulin-zinc suspension* - This refers to older formulations like **Lente** and **Ultralente** insulins, which had intermediate to long durations, but not as long as modern ultra-long-acting insulins. - While prolonged compared to regular insulin, their duration of action was typically around 24-36 hours, making them shorter-acting than degludec. *Neutral protamine Hagedorn (NPH)* - NPH is an **intermediate-acting insulin** with a duration of action usually between 10-18 hours. - Its action profile involves a peak, and it typically requires twice-daily dosing, unlike ultra-long-acting insulins. *Protamine-zinc insulin* - This is an older, **long-acting insulin** formulation that had a duration of action around 24-36 hours. - It has largely been replaced by newer, more predictable basal insulins like glargine and degludec due to issues with variability in absorption.

Question 763: Intranasal calcitonin is used for:

A. Osteoporosis (Senile)
B. Paget's disease
C. Hypercalcemia
D. Osteoporosis (Post-menopausal) (Correct Answer)

Explanation: ***Osteoporosis (Post-menopausal)*** - **Calcitonin** inhibits osteoclast activity, reducing bone resorption and slowing bone loss, which is particularly beneficial in **post-menopausal osteoporosis**. - Intranasal calcitonin is approved for the treatment of **post-menopausal osteoporosis** in women who are at least 5 years past menopause. *Osteoporosis (Senile)* - While calcitonin can have some effect, it is generally **less effective** for senile osteoporosis compared to other agents like bisphosphonates. - Senile osteoporosis primarily results from **age-related bone formation decrease** rather than solely increased bone resorption. *Paget's disease* - **Calcitonin** can be used in Paget's disease to reduce bone turnover and pain, but it is **not the first-line treatment**, and bisphosphonates are generally more effective. - Paget's disease involves disorganized bone remodeling, and while calcitonin helps, it's not the primary indication for the intranasal form. *Hypercalcemia* - **Calcitonin** can acutely lower **serum calcium levels** by inhibiting osteoclast activity and promoting renal calcium excretion. - However, for sustained management of severe hypercalcemia, other interventions like hydration, diuretics, and bisphosphonates are typically more effective and primary treatments.

Question 764: Which oral hypoglycemic drug causes an Antabuse-like effect?

A. Chlorpropamide (Correct Answer)
B. Gliclazide
C. Acarbose
D. Metformin

Explanation: ***Chlorpropamide*** - Chlorpropamide, a **first-generation sulfonylurea**, can inhibit aldehyde dehydrogenase, leading to the accumulation of **acetaldehyde** when alcohol is consumed. - This accumulation causes an **Antabuse-like effect**, characterized by flushing, nausea, vomiting, dizziness, and headache. *Acarbose* - Acarbose is an **alpha-glucosidase inhibitor** that delays carbohydrate absorption from the gut. - Its side effects primarily include gastrointestinal disturbances like **flatulence, diarrhea, and abdominal pain**, and it does not cause an Antabuse-like reaction. *Metformin* - Metformin, a **biguanide**, primarily works by reducing hepatic glucose production and improving insulin sensitivity. - Its common side effects are **gastrointestinal upset** (e.g., nausea, diarrhea) and it can rarely cause **lactic acidosis**, but it does not interact with alcohol to produce an Antabuse-like effect. *Gliclazide* - Gliclazide is a **second-generation sulfonylurea** that stimulates insulin release from pancreatic beta cells. - While all sulfonylureas can potentially cause hypoglycemia, gliclazide is less likely to produce a significant Antabuse-like reaction compared to first-generation agents like chlorpropamide.

Question 765: Which sulfonylurea is used in the treatment of neurogenic diabetes insipidus?

A. Glyburide
B. Chlorpropamide (Correct Answer)
C. Glipizide
D. Tolbutamide

Explanation: ***Chlorpropamide*** - **Chlorpropamide** is the only sulfonylurea that has an **antidiuretic effect** and can enhance the action of **antidiuretic hormone (ADH)** by increasing the release of ADH and potentiating its action on the renal tubules. - This effect makes it useful in some cases of partial **neurogenic diabetes insipidus**, where there's still some ADH production. *Glyburide* - **Glyburide** is a second-generation sulfonylurea primarily used for **type 2 diabetes mellitus** to increase insulin secretion. - It does not have significant **antidiuretic properties** that would be beneficial in diabetes insipidus. *Glipizide* - **Glipizide** is another second-generation sulfonylurea, similar to glyburide, primarily used to stimulate **insulin release** from pancreatic beta cells in **type 2 diabetes**. - It lacks the specific mechanism of action required to treat **diabetes insipidus**. *Tolbutamide* - **Tolbutamide** is a first-generation sulfonylurea that also works by stimulating **insulin secretion** from the pancreas. - While it is a sulfonylurea, it does not possess the unique **antidiuretic properties** of chlorpropamide that are required for treating diabetes insipidus.

Question 766: Which of the following drugs used to treat type II diabetes mellitus causes weight loss?

A. Metformin (Correct Answer)
B. Glimepiride
C. Repaglinide
D. Gliclazide

Explanation: ***Metformin*** - **Metformin** often leads to **modest weight loss** as it improves insulin sensitivity and reduces hepatic glucose production. - It works by activating **AMPK**, which can suppress appetite and reduce fat storage. *Glimepiride* - **Glimepiride** is a **sulfonylurea** that stimulates insulin release from pancreatic beta cells. - This mechanism often leads to **weight gain** due to increased insulin levels. *Repaglinide* - **Repaglinide** is a **meglitinide**, which, like sulfonylureas, increases insulin secretion in a glucose-dependent manner. - This increased insulin secretion can also result in **weight gain**. *Gliclazide* - **Gliclazide** is another **sulfonylurea** that works by increasing insulin secretion from the pancreas. - Similar to other sulfonylureas, its use is commonly associated with **weight gain**.

Question 767: A depot contraceptive, DMPA, is to be given every:

A. 1 month
B. 2 months
C. 3 months (Correct Answer)
D. 6 months

Explanation: ***3 months*** - **Depot medroxyprogesterone acetate (DMPA)**, commonly known as **Depo-Provera**, is a highly effective injectable contraceptive. - It works by preventing ovulation and thickening cervical mucus and is administered as an **intramuscular injection** every **12 to 13 weeks** (approximately 3 months). *1 month* - While some **combined oral contraceptives** and **vaginal rings** are used on a monthly cycle, DMPA is not [1]. - Administering DMPA monthly would result in unnecessarily high hormone levels and potential side effects. *2 months* - Administering DMPA every two months is not the standard dosing regimen for this contraceptive. - The efficacy and duration of action of DMPA are well-established for a 3-month interval. *6 months* - The contraceptive effect of DMPA typically lasts for about 3 months; therefore, waiting 6 months between injections would leave the user unprotected for a significant period. - Other long-acting reversible contraceptives (LARCs) like some **subdermal implants** or **intrauterine devices (IUDs)** can provide protection for longer periods, but not DMPA.

Question 768: What is the most common gastrointestinal side effect of oral contraceptives?

A. Decreased appetite
B. Weight loss
C. Nausea (Correct Answer)
D. Constipation

Explanation: ***Nausea*** - **Nausea** is a very common gastrointestinal side effect of oral contraceptives, especially during the initial weeks of use, due to the **estrogen component**. - This side effect often **improves over time** as the body adjusts, or can be managed by taking the pill with food or at bedtime. *Weight loss* - Oral contraceptives are **not typically associated with weight loss**; in fact, some users may experience slight weight gain, although studies show no consistent significant effect. - Changes in weight are more often due to **fluid retention** rather than true fat loss. *Decreased appetite* - **Decreased appetite** is not a common side effect of oral contraceptives; rather, some individuals might experience an increased appetite due to hormonal fluctuations. - The hormonal effects on metabolism and appetite are **varied and not consistently demonstrated** to lead to decreased appetite. *Constipation* - **Constipation** is not a frequent gastrointestinal side effect of oral contraceptives; rather, some users may experience changes in bowel habits, but **diarrhea is more commonly reported** than constipation when GI issues occur. - Hormonal contraceptives primarily affect the gut through **estrogen and progestin**, leading to various effects, but constipation is not a predominant one.

Question 769: What is the estrogen component in the contraceptive formulation MALA-N?

A. Ethinyl estradiol 30 mcg (Correct Answer)
B. Ethinyl estradiol 50 mcg
C. Progesterone 10 mg
D. Norgestrel 300 mcg

Explanation: ***Ethinyl estradiol 30 mcg*** - MALA-N is a combined oral contraceptive that contains **ethinyl estradiol** as its estrogen component. - The standard dose of ethinyl estradiol in this formulation is **30 mcg**. *Ethinyl estradiol 50 mcg* - While ethinyl estradiol is the correct estrogen, a 50 mcg dose is generally considered a **high-dose estrogen** and is less commonly used in modern combined oral contraceptives due to a higher risk of side effects like **venous thromboembolism**. - Most current formulations, including MALA-N, use lower doses of estrogen for improved safety profiles. *Progesterone 10 mg* - **Progesterone** is a natural hormone, whereas the progestin in MALA-N is **norgestrel**, a synthetic progestin. - Progesterone is used in some contraceptive methods, but not as the estrogen component in combined oral contraceptives like MALA-N. *Norgestrel 300 mcg* - **Norgestrel** is a **progestin**, not an estrogen, and acts as the progestin component in MALA-N, usually at a dose of 300 mcg or more depending on the formulation. - Progestins primarily work by thickening cervical mucus, inhibiting ovulation, and thinning the uterine lining.

Question 770: All of the following statements regarding metformin are true, except:

A. Acts by increasing insulin secretion (Correct Answer)
B. It causes little or no hypoglycemia in non diabetic subjects
C. When given with alcohol, increases risk of lactic acidosis
D. Increases peripheral utilisation of glucose and decreases absorption of glucose from intestine

Explanation: ***Acts by increasing insulin secretion*** - Metformin primarily acts by decreasing **hepatic glucose production** and increasing **insulin sensitivity** in peripheral tissues. - It does not directly stimulate insulin secretion from pancreatic beta cells, unlike sulfonylureas. *It causes little or no hypoglycemia in non diabetic subjects* - Metformin is considered a **euglycemic agent** because it rarely causes hypoglycemia when used as monotherapy, even in non-diabetic individuals. - Its mechanism of action primarily involves reducing glucose output from the liver and improving insulin action, rather than overtly lowering blood sugar. *When given with alcohol, increases risk of lactic acidosis* - Co-administration of metformin with alcohol significantly increases the risk of **lactic acidosis**, especially in patients with pre-existing renal impairment or liver disease. - Both metformin and alcohol can impair lactate metabolism, leading to its accumulation in the bloodstream. *Increases peripheral utilisation of glucose and decreases absorption of glucose from intestine* - Metformin **enhances glucose uptake and utilization** in peripheral tissues, particularly skeletal muscle, by improving insulin sensitivity. - It also has a minor effect on the gastrointestinal tract, causing a **modest decrease in glucose absorption** from the intestine, contributing to its overall glucose-lowering effect.

Practice by Chapter

Hypothalamic and Pituitary Hormones

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Thyroid Drugs and Antithyroid Agents

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Insulin and Oral Hypoglycemic Agents

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Adrenocorticosteroids

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Sex Hormones: Estrogens and Progestins

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Androgens and Anabolic Steroids

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Hormonal Contraceptives

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Drugs Affecting Calcium Metabolism

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Drugs for Osteoporosis

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Pharmacological Management of Obesity

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