Vasopressin is targets the collecting ducts of the kidney and increases the concentration of aquaporins for reabsorption of water. When would vasopressin be released and what is it released by? a. When the osmolarity of plasma decreases; the adrenal cortex b. A decrease in plasma volume; the hypothalamus c. A decrease in MAP; the neurohypophysis d. Dehydration is occurring; the parathyroid.\