Which of the following is not associated with hypothyroidism?

Correct Answer: B

Rationale: The correct answer is B: Weight loss. Hypothyroidism is characterized by an underactive thyroid gland, leading to a decreased metabolic rate. This typically results in weight gain, not weight loss. Choices A, C, and D are all associated with hypothyroidism. Loss of libido can occur due to hormonal imbalances, cardiac failure can result from the decreased metabolic rate affecting the heart, and organic psychosis can be a symptom of severe untreated hypothyroidism.

Correct Answer: A

Rationale: The correct answer is A: Diarrhea. Addison's disease is a condition where the adrenal glands do not produce enough hormones. Diarrhea is not a typical symptom of Addison's disease. The characteristic features include fatigue, weakness, weight loss, dizziness (B), hyperpigmentation, low blood pressure, dehydration (D), and skin changes like dermatitis is common (C). Therefore, diarrhea does not align with the typical symptoms of Addison's disease.

Correct Answer: B

Rationale: The correct answer is B: Inhibition of the function of thyroid peroxidase. Propylthiouracil inhibits thyroid peroxidase, an enzyme essential for thyroid hormone synthesis. By blocking this enzyme, propylthiouracil reduces the production of thyroid hormones, helping to manage hyperthyroidism in Graves' disease. Explanation: 1. Propylthiouracil directly inhibits thyroid peroxidase, unlike other antithyroid medications that target different mechanisms. 2. Inhibition of thyroid peroxidase leads to decreased synthesis of thyroid hormones, effectively controlling hyperthyroidism. 3. Other choices are incorrect because propylthiouracil does not primarily affect the production of thyroid-stimulating immunoglobulins (choice A), peripheral conversion of T4 to T3 (choice C), or iodine organification (choice D) in the treatment of Graves' disease. In summary, the inhibition of thyroid peroxidase by

Correct Answer: C

Rationale: The correct answer is C: SIADH. Secondary hyperaldosteronism is characterized by increased aldosterone production due to factors outside of the adrenal glands, such as increased renin-angiotensin-aldosterone system activation. SIADH does not involve aldosterone, but rather involves inappropriate secretion of antidiuretic hormone leading to hyponatremia. In contrast, congestive cardiac failure, nephrotic syndrome, and cirrhosis of the liver can all lead to secondary hyperaldosteronism due to mechanisms such as decreased effective circulating volume, renal hypoperfusion, and increased angiotensin II levels, respectively.

Correct Answer: A

Rationale: The correct answer is A because parathyroid hormone does not directly stimulate osteoblasts to increase bone formation. Instead, it indirectly increases bone resorption by stimulating osteoclasts. Parathyroid hormone also increases calcium reabsorption from the distal tubule of the kidney (choice C) and inhibits phosphate reabsorption in the proximal tubule of the kidney (choice D). By understanding the physiological actions of parathyroid hormone, we can deduce that direct stimulation of osteoblasts is not one of its functions.