The antidiuretic hormone or ADH is a posterior pituitary hormone which conserves water by decreasing urine, as suggested by the name. If you want to get the complete information regarding it then this video is for you. timeline: 0:00 introduction 1:00 stimulus 4:31 mechanism of ADH 12:00 plasma osmolality 13:40 vasoconstriction 15:13 hyposecretion of ADH (Diabetes insipidus) 16:26 hypersecretion of ADH (SIADH)