Q- Which one of the following glucocorticoids can cause sodium and water retention?
A- Betamethasone
B- Cortisol
C- Dexamethasone
D- Triamcinolone
B- Cortisol- Cortisol (hydrocortisone) has significant mineralocorticoid activity, leading to sodium and water retention. Betamethasone, dexamethasone, and triamcinolone have minimal to no mineralocorticoid effects.
Q- Which one of the following drugs acts mainly by blocking the synthesis of leukotrienes?
A -Cromolyn
B- Ipratropium
C- Montelukast
D- Zileuton
D- Zileuton- Zileuton inhibits 5-lipoxygenase, the enzyme responsible for leukotriene synthesis. Montelukast blocks leukotriene receptors, not their synthesis. Cromolyn stabilizes mast cells, and ipratropium is an anticholinergic bronchodilator.
Q- Which of the following controls the secretion of thyrotropin?
A- Concentration of iodine in the thyroid gland
B- Concentration of thyroid hormones in the blood
C- Concentration of thyroid hormones in the thyroid gland
D- Concentration of thyrotropin in the pituitary gland
B- Concentration of thyroid hormone in the blood- Thyrotropin (TSH) secretion is controlled by negative feedback from circulating thyroid hormones (T3 and T4). When blood levels of T3/T4 rise, TSH secretion decreases; when they fall, TSH increases.
