Okay medical blogosphere, let’s figure this one out (comments are open!). Is there a physiologic mechanism to “breaking the seal,” or is it just a drinking myth? (Breaking the seal, if you’re not familiar with the term, refers to the idea that if you’re out drinking, once you start peeing, then you’re going to have to go urinate every 10-20 minutes after that. “Don’t break the seal!” means don’t start peeing, ’cause then you’ll never stop!)
From Goodman and Gillman’s Pharmacology:
Alcohol inhibits the release of vasopressin (antidiuretic hormone; see Chapter 29) from the posterior pituitary gland, resulting in enhanced diuresis (Leppaluoto et al., 1992). The volume loading that accompanies imbibing complements the diuresis that occurs as a result of reduced vasopressin secretion. Alcoholics have less urine output than do control subjects in response to a challenge dose with ethanol, suggesting that tolerance develops to the diuretic effects of ethanol (Collins et al., 1992). Alcoholics withdrawing from alcohol exhibit increased vasopressin release and a consequent retention of water, as well as dilutional hyponatremia.
Vasopressin (ADH, antidiuretic hormone) causes your kidneys to reabsorb free water molecules, to maintain your sodium osmolality, so knock that out and you’re going to be peeing lots of dilute urine, making you hypernatremic. Combine that with ethanol’s peripheral vasodilation, making your kidneys think you’re hypovolemic (even though you’ve been drinking lots of fluid), and they’re going to try to clamp down to reabsorb all the possible sodium they can… aaand that’s all I’ve got. Maybe it’s just a feed-forward positive feedback relationship with the continued filtering of the kidneys, since they don’t realize ADH isn’t being released? I don’t think it really matters if you stop drinking or not.
I swear I experience this all the time, but maybe it’s just the drunkness and rapid passage of time. I’m stumped.
(Excuse: Was reviewing phys today for Anesthesia which starts on Monday, and boy can my mind wander.)