Endocrine Pharmacology

Endocrine Pharmacology Indian Medical PG Question 1: All of the following hormones have cell surface receptors except:

• A. Thyroxine (Correct Answer)
• B. Insulin
• C. Adrenalin
• D. Growth Hormone

Endocrine Pharmacology Explanation: ***Thyroxine*** - **Thyroxine** (T4) is a **lipid-soluble thyroid hormone** that readily crosses the cell membrane to bind to **intracellular nuclear receptors** in the nucleus. - This binding leads to changes in gene expression, which then mediates its metabolic effects. - Unlike peptide hormones, thyroid hormones do not require cell surface receptors. *Insulin* - **Insulin** is a **peptide hormone** that binds to specific **cell surface receptors** (tyrosine kinase receptors) on target cells. - This binding initiates a signaling cascade that regulates glucose uptake and metabolism. *Adrenalin* - **Adrenalin** (epinephrine) is a **catecholamine hormone** that binds to **G protein-coupled receptors (GPCRs)** on the cell surface. - This binding triggers intracellular signaling pathways, leading to the "fight-or-flight" response. *Growth Hormone* - **Growth hormone** is a **protein hormone** that binds to **cell surface receptors** (cytokine receptors) on target cells. - This interaction activates the JAK-STAT signaling pathway, promoting growth and metabolism.

Endocrine Pharmacology Indian Medical PG Question 2: In which of the following situations is intensive management of diabetes typically avoided?

• A. Stable diabetes with no complications
• B. Diabetes in a well-controlled state
• C. Diabetes with stable renal function post-transplant
• D. Diabetes with acute myocardial infarction (Correct Answer)

Endocrine Pharmacology Explanation: Diabetes with acute myocardial infarction - In the setting of **acute myocardial infarction (AMI)**, aggressive **glucose lowering** can increase the risk of **hypoglycemia** and is generally avoided due to potential for worse outcomes [1]. - The primary focus in AMI is on cardiovascular stabilization, and overly tight glycemic control can lead to **metabolic stress** and adverse events, particularly in patients with a high prevalence of cardiovascular disease [1]. *Stable diabetes with no complications* - Patients with **stable diabetes** and no complications are often candidates for **intensive management** to prevent long-term microvascular and macrovascular complications [1]. - The goal is to maintain near-normal glucose levels to reduce the risk of future disease progression [1]. *Diabetes in a well-controlled state* - **Well-controlled diabetes** usually indicates that current management is effective, but further **intensification** might be considered to achieve optimal glycemic targets and minimize long-term risks if there's room for improvement. - This scenario does not inherently contraindicate intensive management, as it could still benefit from fine-tuning to achieve even tighter control without undue risk. *Diabetes with stable renal function post-transplant* - Patients with **diabetes** and stable **renal function post-transplant** often require careful but often intensive diabetes management to preserve graft function and prevent cardiovascular complications. - While medication adjustments are necessary due to altered renal clearance, the goal remains to achieve good glycemic control, potentially through intensive strategies.

Endocrine Pharmacology Indian Medical PG Question 3: Treatment of choice in childhood thyrotoxicosis is:

• A. Carbimazole (Correct Answer)
• B. Radioiodine therapy
• C. Surgical intervention
• D. Lugol's iodine solution

Endocrine Pharmacology Explanation: ***Carbimazole*** - **Antithyroid medications** like carbimazole are the **first-line treatment** for childhood thyrotoxicosis due to their efficacy in controlling hormone levels and lower risk compared to other interventions. - It works by inhibiting the synthesis of **thyroid hormones**, allowing for a gradual resolution of symptoms. *Radioiodine therapy* - This treatment is generally avoided in children due to potential long-term risks, including an increased risk of **thyroid cancer** and the need for lifelong **thyroid hormone replacement**. - It is typically reserved for older adolescents or cases where other treatments have failed. *Surgical intervention* - **Thyroidectomy** is usually considered a last resort in children due to the risks associated with surgery, such as damage to the **parathyroid glands** or **recurrent laryngeal nerve**. - It may be indicated in cases of very large goiter, drug intolerance, or non-compliance with medical therapy. *Lugol's iodine solution* - **Lugol's iodine** is primarily used for **short-term preparation** before thyroid surgery to decrease the vascularity of the gland and in **thyroid storm** to block hormone release. - It is not a definitive long-term treatment for childhood thyrotoxicosis due to its transient effect and potential for rebound hyperthyroidism.

Endocrine Pharmacology Indian Medical PG Question 4: Which of the following statements best describes the mechanism of action of insulin on target cells?

• A. Insulin binds to a receptor on the outer surface of the plasma membrane, activating adenylate cyclase through the Gs protein.
• B. Insulin binds to a cytoplasmic receptor and is transferred as a hormone receptor complex to the nucleus to modulate gene expression.
• C. Insulin enters the cell and causes the release of calcium ions from intracellular stores.
• D. Insulin binds to a transmembrane receptor on the outer surface of the plasma membrane, activating the tyrosine kinase in the cytosolic domain of the receptor. (Correct Answer)

Endocrine Pharmacology Explanation: ***Insulin binds to a transmembrane receptor on the outer surface of the plasma membrane, activating the tyrosine kinase in the cytosolic domain of the receptor.*** - **Insulin** is a **peptide hormone** and cannot freely pass through the lipid bilayer, thus it binds to a **transmembrane receptor** on the cell surface. - This binding leads to the activation of the receptor's intrinsic **tyrosine kinase activity** in the intracellular domain, initiating a signaling cascade. *Insulin binds to a cytoplasmic receptor and is transferred as a hormone receptor complex to the nucleus to modulate gene expression.* - This mechanism describes the action of **steroid hormones**, which are lipid-soluble and can cross the cell membrane, binding to **intracellular receptors**. - **Insulin** acts via a **cell surface receptor** and its downstream effects are mediated through signal transduction pathways, not direct nuclear translocation. *Insulin binds to a receptor on the outer surface of the plasma membrane, activating adenylate cyclase through the Gs protein.* - This mechanism is characteristic of **G-protein coupled receptors (GPCRs)**, which activate or inhibit enzymes like adenylate cyclase via G-proteins to produce second messengers like cyclic AMP. - The **insulin receptor** is a **receptor tyrosine kinase**, not a GPCR, and does not directly activate adenylate cyclase via Gs protein. *Insulin enters the cell and causes the release of calcium ions from intracellular stores.* - While some hormones and neurotransmitters can trigger the release of intracellular **calcium ions**, this is typically mediated by specific pathways (e.g., GPCRs linked to phospholipase C). - **Insulin** does not directly enter target cells to cause calcium release; its actions are primarily mediated through receptor tyrosine kinase signaling pathways.

Endocrine Pharmacology Indian Medical PG Question 5: Which of the following is the platinum-based chemotherapeutic agent used as first-line treatment for ovarian carcinoma?

• A. Cyclophosphamide
• B. Methotrexate
• C. Cisplatin (Correct Answer)
• D. Dacarbazine

Endocrine Pharmacology Explanation: ***Cisplatin*** - **Cisplatin** is a platinum-based chemotherapy drug that forms **DNA cross-links**, inhibiting DNA synthesis and leading to the death of rapidly dividing cells, making it highly effective against **ovarian carcinoma**. - It is a cornerstone of chemotherapy regimens for ovarian cancer, often used in combination with other agents such as paclitaxel. *Methotrexate* - **Methotrexate** is an **antimetabolite** that inhibits dihydrofolate reductase, thereby interfering with DNA synthesis. - While it is used in various cancers like leukemia, lymphoma, and some solid tumors (e.g., breast cancer, gestational trophoblastic disease), it is **not a primary recommended drug for ovarian carcinoma**. *Cyclophosphamide* - **Cyclophosphamide** is an **alkylating agent** that causes DNA damage, leading to cell death. - It is used in many cancers, including lymphoma, breast cancer, and some leukemias, but it is **not a first-line or primary agent for ovarian carcinoma** in contemporary treatment guidelines. *Dacarbazine* - **Dacarbazine** is an **alkylating agent** primarily used in the treatment of **malignant melanoma** and Hodgkin lymphoma. - It is **not indicated for the treatment of ovarian carcinoma**.

Endocrine Pharmacology Flashcard 1 of 5

Question: Danazol is a synthetic _____ that acts as a partial agonist at androgen receptors

Answer: androgen

Endocrine Pharmacology Flashcard 2 of 5

Question: Thyroid, Pituitary, & Adrenal _____ and bromocriptine are D2 receptor agonists, which may be used to treat acromegaly by inhibiting secretion of GH from the anterior pituitary

Answer: Cabergoline

Endocrine Pharmacology Flashcard 3 of 5

Question: _____ can cause euglycemic diabetic ketoacidosis (DKA)

Answer: SGLT2 inhibitors::OHA

Endocrine Pharmacology Flashcard 4 of 5

Question: Thyroid, Pituitary, & Adrenal _____ and calcitonin are useful in the management of Paget disease, which is characterized by uncontrolled osteoclast resorption with secondary disorganized bone formation

Answer: Bisphosphonates

Endocrine Pharmacology Flashcard 5 of 5

Question: Monotherapy of _____ and insulin have a weight-gain effect.

Answer: sulfonylureas