The most prominent action of bromocriptine is:

Correct Answer: A

Rationale: The correct answer is A: Dopamine D2 agonism. Bromocriptine is a dopamine D2 receptor agonist, meaning it activates D2 receptors. This leads to inhibiting prolactin secretion, making it a treatment for hyperprolactinemia. Dopamine D2 antagonism (B) would have the opposite effect. Dopamine D1 antagonism (C) is not a prominent action of bromocriptine. α adrenergic antagonism (D) is not related to the mechanism of action of bromocriptine.

Correct Answer: A

Rationale: Step-by-step rationale: 1. Thyroxine increases basal metabolic rate. 2. This leads to increased energy expenditure. 3. Increased energy expenditure can lead to negative nitrogen balance. 4. Therefore, induction of negative nitrogen balance is an action of thyroxine. 5. The other choices are incorrect as thyroxine does reduce plasma cholesterol level, fall in plasma free fatty acid level, and rise in blood sugar level.

Correct Answer: B

Rationale: Carbimazole inhibits the oxidation of iodide by blocking the enzyme thyroid peroxidase. This enzyme is crucial for converting iodide to iodine, a key step in thyroid hormone synthesis. By inhibiting this step, carbimazole effectively reduces the production of thyroid hormones. Choice A is incorrect as iodide trapping is not directly affected by carbimazole. Choice C is incorrect as proteolysis of thyroglobulin is not the target of carbimazole. Choice D is incorrect as carbimazole does not interfere with the synthesis of thyroglobulin protein itself.

Correct Answer: B

Rationale: The correct answer is B: Preoperatively for 10-15 days. Lugol's iodine is used preoperatively in hyperthyroidism to reduce vascularity and size of the thyroid gland, making surgery safer. Administering it for 10-15 days before surgery allows for optimal effects. Choice A is incorrect because Lugol's iodine is not used as long term definitive monotherapy due to its potential side effects and limitations. Choice C is incorrect as Lugol's iodine is not typically used postoperatively for 10-15 days. Choice D is incorrect because Lugol's iodine is not used as an adjuvant to carbimazole for long term therapy; carbimazole is commonly used as a long-term therapy for hyperthyroidism.

Correct Answer: A

Rationale: Insulin release is primarily stimulated by glucose. Ketone bodies are produced during fasting or low-carb diets and do not directly stimulate insulin release. Glucagon stimulates glycogen breakdown and opposes insulin. Vagal stimulation can enhance insulin release through parasympathetic nervous system activation. Alpha adrenergic agonists like epinephrine inhibit insulin release. Therefore, the correct answer is A as ketone bodies do not directly augment insulin release.