I mean that the body most won't respond to signals to reabsorb water from the bladder because of weak QVPR2 activity.
AVPR2 only shows up (significantly) in the kidneys. It pumps water back from the bladder to the bloodstream. AVPR1 and AVPR3 show up in the brain (and drive/control any hormonal response tied to water availability/quality/safety-to-access. Including territorial mammals marking territory.)
Vasopressin is actually a mirror-image of oxytocin, with a few hundred million years of divergent mutations. Unique to mammals. That's why mammals are the only vertebrates that independently, separately, regulate water and ions. (Thus, sweating, lactation, crying, uncalcified placenta vs egg, etc.)
So the brain keeps pumping out vasopressin (in response to dehydration-induced corticotropin-releasing factor). This leads to water "running right through". And high baseline vasopressin levels that go even higher with dehydration.
Less commonly, especially for men, the body overreacts to vasopressin. Excessive vasopressin 2 receptor efficacy or transcription leads to low baseline vasopressin. Low vasopressin 'magnifies' any oxytocin activity. Leads to "human-hyperstimulated" autism and high innate trust in unfearful situations. Also often leads to low territory/spatial mapping capacity.
