The pituitary hormone vassopressen or AntiDieretic hormone ADH is related to the kidneys.

With the high volume of urination you'll probably also need more of electrolytes and maybe water soluble vitamins--C, some Bs, etc. I suppose you are vulnerable to getting dizzy upon standing.

"Vasopressin is a peptide of 9 amino acids (Cys-Tyr-Phe-Gln-Asn-Cys-Pro-Arg-Gly). It is also known as ... the antidiuretic hormone (ADH).

Vasopressin acts on the collecting ducts of the kidney to facilitate the reabsorption of water into the blood. Thus it acts to reduce the volume of urine formed (giving it its name of antidiuretic hormone).

Link to discussion of kidney physiology.
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/K/Kidney.html

A deficiency of vasopressin or
inheritance of mutant genes for its receptor (called V2)
leads to excessive loss of urine, a condition known as diabetes insipidus. The most severely-afflicted patients may urinate as much as 30 liters (almost 8 gallons!) of urine each day. The disease is accompanied by terrible thirst, and patients must continually drink water to avoid dangerous dehydration."
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/Pituitary.html