Final answer:
Arginine vasopressin, also known as antidiuretic hormone (ADH), is not identical to atrial natriuretic peptide (ANP) as they have contrasting roles in blood pressure regulation and water balance in the body; ADH promotes water reabsorption and vasoconstriction, whereas ANP promotes diuresis and vasodilation.
Step-by-step explanation:
The question regarding which substance is identical to arginine vasopressin is related to the topic of hormones and their functions. Arginine vasopressin, also known as antidiuretic hormone (ADH), is a peptide hormone produced by the hypothalamus and subsequently released from the posterior pituitary. Its primary role is to regulate water balance in the body by increasing water reabsorption in the kidneys. This is achieved through the insertion of aquaporins into the collecting ducts.
Additionally, ADH has vasoconstrictive properties, which increase blood pressure in situations such as hemorrhaging. In contrast, the atrial natriuretic peptide (ANP) acts as a vasodilator to lower blood pressure. ANP prompts diuresis by inhibiting sodium reabsorption in the renal tubules, leading to an excretion of water and a decrease in blood volume and pressure. While ADH and ANP both influence blood pressure and water balance, they have opposing effects and are not identical.