Which association is least appropriate?

Correct Answer: D

Rationale: Corticotropes secrete ACTH, not cortisol directly.

Correct Answer: B

Rationale: GLUT transporters (e.g., GLUT4) facilitate glucose diffusion across membranes, not requiring energy directly.

Correct Answer: A

Rationale: Uric acid is a product of purine (e.g., adenine, guanine) catabolism, not pyrimidines, glutamine, or urea.

Correct Answer: B

Rationale: Cholera toxin increases cAMP, opening Cl^- channels, causing diarrhea. Na^+/glucose co-transport remains effective (basis for ORS).

Correct Answer: D

Rationale: Acetylcholine stimulates glucagon via vagal input; somatostatin inhibits, FFAs and α-agonists can stimulate, GABA has less direct effect.