[{"from": "human", "value": "Provide a brief overview of this molecule. [C][C][C][C][C][=N][C][=Branch2][Ring2][Ring2][=C][Branch2][Ring1][=C][N][Ring1][Branch1][C][C][=C][C][=C][Branch1][Branch1][C][=C][Ring1][=Branch1][C][=C][C][=C][C][=C][Ring1][=Branch1][C][=N][N][N][=N][Ring1][Branch1][C][O][Cl]"}, {"from": "gpt", "value": "The molecule is a non-peptide angiotensin II antagonist with antihypertensive activity. Upon administration, losartan and its active metabolite selectively and competitively blocks the binding of angiotensin II to the angiotensin I (AT1) receptor. This blocks the vasoconstricting and aldosterone-secreting actions of angiotensin II, leading to a decrease in blood pressure. Angiotensin II, formed from angiotensin I by angiotensin-converting enzyme (ACE), stimulates the adrenal cortex to synthesize and secrete aldosterone, which decreases the excretion of sodium and increases the excretion of potassium. Angiotensin II also acts as a vasoconstrictor in vascular smooth muscle."}]