Somatostatin inhibits the release of:

Correct Answer: D

Rationale: Somatostatin inhibits the release of growth hormone, insulin, and thyrotropin. It acts as a hormone and neurotransmitter, regulating the endocrine system. By inhibiting these hormones, somatostatin helps maintain homeostasis in the body. Therefore, the correct answer is D. Choices A, B, and C are incorrect because somatostatin does not selectively inhibit only one of these hormones; it affects all of them.

Correct Answer: B

Rationale: The correct answer is B: Cryptorchism in a boy less than 7 years old. Gonadotropins are not indicated in cryptorchism as it is a condition where one or both testes fail to descend into the scrotum. Gonadotropins are used to treat conditions like hypogonadotrophic hypogonadism, amenorrhoea, infertility, and polycystic ovaries by stimulating the production of sex hormones. For the other choices: A) Hypogonadotrophic hypogonadism in males - correct, as gonadotropins can help stimulate testosterone production. C) Amenorrhoea and infertility in women - correct, as gonadotropins can help induce ovulation. D) Polycystic ovaries - correct, as gonadotropins can help regulate hormone levels and promote ovulation.

Correct Answer: D

Rationale: The correct answer is D: Serum TSH level. Serum TSH level is the most reliable guide for adjusting thyroxine dose in hypothyroidism because it directly reflects the body's feedback mechanism to regulate thyroid hormone levels. Elevated TSH indicates the body is trying to stimulate the thyroid gland to produce more hormone, suggesting the need for an increase in thyroxine dose. Conversely, low TSH levels indicate potential over-replacement, necessitating a reduction in thyroxine dose. Pulse rate (A) and body weight (B) can be influenced by various factors and are not specific indicators of thyroid hormone levels. Serum thyroxine level (C) can be affected by the timing of the last medication dose and does not provide feedback on the body's overall thyroid status like TSH does.

Correct Answer: C

Rationale: Step-by-step rationale for correct answer (C): 1. Radioactive iodine destroys overactive thyroid tissue, reducing hormone production. 2. Unlike anti-thyroid medications (A and B), radioactive iodine does not directly inhibit thyroid function. 3. Sodium thiocyanate (D) inhibits iodine uptake by the thyroid, potentially leading to goiter. Summary of incorrect choices: A. Propyl thiouracil and B. Carbimazole are anti-thyroid medications that can cause goiter in overdose. D. Sodium thiocyanate can lead to goiter by interfering with iodine uptake.

Correct Answer: C

Rationale: Correct Answer: C) Carbimazole does not produce an active metabolite. Rationale: 1. Carbimazole is a prodrug that is converted to its active form, methimazole, in the body. 2. Methimazole is the active compound responsible for inhibiting thyroid hormone production. 3. Propylthiouracil, on the other hand, directly inhibits thyroid hormone synthesis without needing conversion. 4. Therefore, Carbimazole differs from propylthiouracil in that it requires metabolic activation to its active form, methimazole, and does not produce a different active metabolite like propylthiouracil does. Summary: A) Incorrect: Carbimazole is not dose to dose less potent compared to propylthiouracil; potency can vary based on individual response. B) Incorrect: Carbimazole actually has a longer plasma half-life compared to propylthiouracil. D) Incorrect: Carbim