Deficiency of a hormone known by this three-letter sequence causes diabetes insipidus; that hormone is released along with oxytocin from the posterior pituitary gland.  
The three-letter sequence is the same.  It represents a non-cancerous condition in which the epithelial cells of the milk ducts in the breast abnormally proliferate.  It also represents a sequence on Drosophila chromosome 2 that codes for serine esterase, laminin subunit a2, and over 200 other proteins, including its namesake (*) enzyme, whose F/S allozymes are sometimes used to illustrate epistatic selection.   Deficiency of a hormone known by this three-letter sequence causes diabetes insipidus; that hormone is released along with oxytocin from the posterior pituitary gland.  "Atypical" Class I isozymes of an enzyme represented by this sequence are found in 85% of Asians and are responsible for the so-called "Asian glow" after drinking alcohol.  For 10 points, give this three-letter sequence that denotes an enzyme responsible for breaking down alcohols or an osmoregulatory hormone also known as vasopressin.
The three-letter sequence is the same.  It represents a non-cancerous condition in which the epithelial cells of the milk ducts in the breast abnormally proliferate.  
{ADH} (3) [DW]