Thiazolidinediones act by:

Correct Answer: A

Rationale: The correct answer is A because thiazolidinediones work by activating peroxisome proliferator-activated receptor gamma (PPAR-γ), which leads to increased glucose uptake and metabolism in muscle and adipose tissues, thereby reducing insulin resistance. It does not reduce carbohydrate absorption from the gut (choice B) or stimulate beta islet cells to produce insulin (choice C). Therefore, the correct answer is A as it directly addresses the mechanism of action of thiazolidinediones.

Correct Answer: D

Rationale: The correct answer is D. Glucocorticoids exert their immunosuppressive effect through multiple mechanisms. A: Glucocorticoids reduce lymphocyte (T and B cells) concentration and inhibit the function of tissue macrophages and other antigen-presenting cells, leading to decreased immune response. B: Glucocorticoids suppress cyclooxygenase II expression, reducing prostaglandin synthesis, which is involved in inflammation. C: Glucocorticoids activate phospholipase A2, reducing prostaglandin and leukotriene synthesis, further dampening the immune response. Therefore, all of the choices (A, B, and C) contribute to the immunosuppressive effect of glucocorticoids.

Correct Answer: B

Rationale: Rationale for choice B being correct: 1. Pantothenic acid is an essential constituent of coenzyme A (CoA). 2. Coenzyme A is crucial for acyl transfer in the TCA cycle and de novo fatty acid synthesis. 3. De novo fatty acid synthesis requires CoA for the activation and transport of acyl groups. 4. Without pantothenic acid, CoA cannot function properly in these metabolic processes. Summary of why other choices are incorrect: A: Pyridoxal phosphate is the active form of vitamin B6, not pantothenic acid. It is involved in amino acid metabolism, not pantothenic acid. C: Pantothenic acid is not primarily known for its antioxidant properties; its main role is as a precursor for CoA. D: The described reactions involve other coenzymes like biotin and vitamin B12, not pantothenic acid.

Correct Answer: A

Rationale: The correct answer is A: TRUE. Clofibrate is the drug of choice for type III hyperlipidemia due to its ability to reduce triglyceride levels. Other choices (B, C, D) are incorrect because they do not accurately reflect the specific drug recommended for type III hyperlipidemia. Choice B is incorrect as clofibrate is indeed the preferred drug for this condition. Choice C is incorrect as not all options are valid in this context. Choice D is incorrect as there is a specific drug recommended for type III hyperlipidemia.

Correct Answer: D

Rationale: Rationale: Glucocorticoid hormones affect bone mineral homeostasis by antagonizing vitamin D-stimulated calcium absorption in the intestines, stimulating renal calcium excretion, and increasing parathyroid hormone-induced bone resorption. Therefore, the correct answer is D, as all these mechanisms contribute to the overall impact of glucocorticoids on bone health. Choices A, B, and C alone do not fully capture the multifaceted effects of glucocorticoids on bone mineral homeostasis.