Actions of growth hormone include the following except:

Correct Answer: C

Rationale: The correct answer is C: Increased carbohydrate utilization. Growth hormone primarily promotes lipolysis, leading to increased fat utilization and protein synthesis. It also induces insulin resistance, resulting in glucose intolerance. However, growth hormone does not directly increase carbohydrate utilization. Therefore, choice C is the exception among the actions of growth hormone.

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: The correct answer is A: Myxoedema. High serum TSH levels indicate primary hypothyroidism, which is characterized by decreased thyroid hormone levels. Myxoedema is a severe form of hypothyroidism where TSH levels increase as the body tries to stimulate the thyroid to produce more hormones. In Grave's disease (B), TSH levels are typically low due to thyroid overactivity. Carcinoma thyroid (C) may present with normal or slightly elevated TSH levels. Toxic nodular goiter (D) is associated with low TSH levels due to autonomous thyroid hormone production.

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.