Final answer:
Erythropoietin has no effect on blood pressure, while antidiuretic hormone, aldosterone, atrial natriuretic peptide, and angiotensin II all affect blood pressure regulation through various mechanisms.
Step-by-step explanation:
The hormone that has no effect on blood pressure among the options provided is erythropoietin. Antidiuretic hormone (ADH), aldosterone, atrial natriuretic peptide (ANP), and angiotensin II all play significant roles in regulating blood pressure. ADH, also known as vasopressin, helps conserve water by reabsorbing it from the kidneys and also acts as a vasoconstrictor, which increases blood pressure.
Aldosterone increases sodium and water reabsorption, which indirectly increases blood pressure. ANP acts as a vasodilator and lowers blood pressure by causing sodium and water excretion. Angiotensin II is a powerful vasoconstrictor that significantly raises blood pressure by increasing sodium and water reabsorption and stimulating thirst.