Abrupt, sudden withdrawal of prednisone (cortisol) is most likely to cause:

Correct Answer: D

Rationale: The correct answer is D: acute adrenal insufficiency. Abrupt withdrawal of prednisone can lead to adrenal insufficiency due to suppression of the adrenal glands' natural cortisol production. This can result in symptoms such as fatigue, weakness, abdominal pain, and low blood pressure. Cushing syndrome (choice A) is caused by excessive cortisol, hypocalcemic tetany (choice B) is due to low calcium levels, and diabetes insipidus (choice C) is a disorder of water balance regulation, not related to prednisone withdrawal.

Correct Answer: D

Rationale: The correct answer is D because ketosis and acidosis are indicative of a rapid and incomplete metabolism of fatty acids. Ketosis occurs when the body breaks down fats for energy, leading to high levels of ketones in the blood. Acidosis results from the accumulation of acidic substances in the body due to incomplete metabolism. Choices A, B, and C are incorrect because excess insulin does not cause ketosis and acidosis, diabetes insipidus is unrelated to these conditions, and ADH (antidiuretic hormone) is not the appropriate treatment for ketosis and acidosis.

Correct Answer: C

Rationale: The correct answer is C, the salivary gland. The salivary gland is not an endocrine gland because it secretes saliva directly into the oral cavity, rather than into the bloodstream like endocrine glands. The pancreas (A) secretes hormones such as insulin and glucagon into the bloodstream. The testes (B) produce hormones like testosterone that are released into the bloodstream. The parathyroid (D) gland secretes parathyroid hormone directly into the bloodstream to regulate calcium levels. In summary, the salivary gland is not considered an endocrine gland because it does not secrete hormones directly into the bloodstream for systemic effects.

Correct Answer: C

Rationale: The correct answer is C: Parathyroid hormone (PTH). The anterior pituitary gland secretes hormones that regulate various bodily functions, such as growth, reproduction, and metabolism. PTH is actually produced by the parathyroid glands, not the anterior pituitary. Human growth hormone (GH), follicle-stimulating hormone (FSH), and thyroid-stimulating hormone (TSH) are all hormones secreted by the anterior pituitary gland. Therefore, C is the correct answer as it is not a hormone produced by the anterior pituitary gland.

Correct Answer: C

Rationale: The correct answer is C: cAMP. Water-soluble hormones, such as adrenaline or glucagon, bind to cell surface receptors and activate a signaling cascade that often involves cAMP as a second messenger. Upon hormone binding, the receptor activates adenylyl cyclase, which converts ATP to cAMP. cAMP then activates protein kinase A, leading to phosphorylation of target proteins, ultimately affecting cellular responses. Explanation for incorrect choices: A: tRNA is involved in protein synthesis, not in signaling pathways of water-soluble hormones. B: ATP is used as an energy source in various cellular processes, but it is not a second messenger in hormone signaling pathways. D: PTH (parathyroid hormone) is a hormone involved in calcium regulation and does not act through cAMP signaling in the same manner as water-soluble hormones.