Effects of diazoxide and hydrochlorothiazide on water permeability and sodium transport in the frog bladder.
The effects of diazoxide and hydrochlorothiazide on vasopressin-induced increments in osmotic water flow and sodium transport across the frog bladder were studied. Diazoxide enhanced the vasopressin-induced osmotic water flow of the bladder, but did not affect the cyclic AMP- or theophylline-induced water flow. Hydrochlorothiazide did not affect the vasopressin-induced water flow. Our results suggest that diazoxide increased the water flow by inhibiting the activity of phosphodiesterase in bladder epithelial cells, whereas hydrochlorothiazide did not. On the other hand, both drugs suppressed the short-circuit current of the bladder membrane and inhibited the Na,K-dependent ATPase activity of the kidney cells. These results suggest that both drugs decreased sodium transport in the bladder by inhibiting Na,K-dependent ATPase activity.
D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000037:antagonists & inhibitors; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D001834:Body Water / Q000378:metabolism*; D003981:Diazoxide / Q000494:pharmacology*; D006852:Hydrochlorothiazide / Q000494:pharmacology*; D010539:Permeability; D011892:Rana catesbeiana; D012964:Sodium / Q000378:metabolism*; D001743:Urinary Bladder / Q000187:drug effects / Q000378:metabolism*; D014667:Vasopressins / Q000494:pharmacology
D006852:Hydrochlorothiazide; D014667:Vasopressins; D012964:Sodium; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D003981:Diazoxide