How come some hormones allow the kidney to reabsorb water, and some allow it to reabsorb salts?electrolights?

Hormones: Different hormones act on different receptors in the tubules of the kidney resulting in different effects. It is like a lock and key. Each hormone fits only its receptor. Stimulation of that receptor results in a specific effect. Antidiuretic hormone stimulates a receptor which open up water channels and allow water to enter. Aldosterone stimulates a sodium potassium pump.