Aglycone is essential for:

Correct Answer: C

Rationale: Aglycone is essential for cardiotonic action because it refers to the non-sugar component of a glycoside molecule that possesses pharmacological activity. In cardiotonic action, the aglycone part of the glycoside compound is responsible for the therapeutic effect on the heart, making choice C the correct answer. Plasma protein binding (choice A), half-life (choice B), and metabolism (choice D) do not directly involve the aglycone component in the context of this question.

Correct Answer: A

Rationale: The correct answer is A: Noradrenalin. Noradrenalin is a sympathomimetic drug that acts on alpha and beta adrenergic receptors, leading to increased cardiac output by increasing heart rate and contractility. Methyldopa (B) and Phenylephrine (C) are vasoconstrictors that can increase blood pressure but not cardiac output. Angiotensinamide (D) is not a drug commonly used to increase cardiac output.

Correct Answer: C

Rationale: The correct answer is C: Triiodothyronine. The thyroid gland produces triiodothyronine (T3) along with its precursor hormone, thyroxine (T4), which are essential for regulating metabolism in the body. T3 is the active form of thyroid hormone that influences various physiological processes. Thyroid-stimulating hormone (TSH) is produced by the pituitary gland to stimulate the thyroid gland to produce T3 and T4, making choice A incorrect. Thyrotropin-releasing hormone (TRH) is produced by the hypothalamus to stimulate the pituitary gland to produce TSH, making choice B incorrect. Thyroglobulin is a protein synthesized by the thyroid gland to store thyroid hormones, not a hormone itself, making choice D incorrect.

Correct Answer: D

Rationale: Progesterone is a hormone essential for pregnancy and menstrual cycle regulation. It is primarily secreted by the corpus luteum after ovulation. Ovarian follicles also produce progesterone during the menstrual cycle. Additionally, granulosa and theca cells in the ovaries contribute to progesterone production. Therefore, the correct answer is D, "All of the above," as all three options play a role in progesterone secretion. Choices A, B, and C individually are incorrect as they only represent specific sources of progesterone production.

Correct Answer: A

Rationale: Step 1: Thromboxane A2 (TXA2) is a potent vasoconstrictor and platelet aggregator. Step 2: Sulotroban is a specific TXA2 receptor antagonist, blocking its effects. Step 3: Zileuton inhibits 5-lipoxygenase, not directly related to TXA2 receptors. Step 4: Zafirleukast is a leukotriene receptor antagonist, not targeting TXA2 receptors. Step 5: Diclofenac is a non-selective NSAID, not a TXA2 receptor antagonist. Summary: Sulotroban is the correct choice as it directly blocks TXA2 receptors, while the other options target different pathways.