This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Biochemistry
[{'content': 'For which is cGMP second messenger? \nSelect and explain. \nA. Thyroxine, B. Atrial natriureptic peptide, C. GH, D. Coiosone', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The binding of ANP to its receptor causes the conversion of GTP to cGMP and raises intracellular cGMPAs a consequence, cGMP activates a cGMP-dependent kinase (PKG or cGK) that phosphorylates proteins at specific serine and threonine residues.In the medullary collecting duct, the cGMP generated in response to ANP may act not only through PKG but also direct modulation of ion channels.Ref: DM Vasudevan, 7th edition, page no: 409', 'role': 'assistant'}]