Effect of acetazolamide and hydrochlorothiazide on vascular volume status.

<p>Rats (n = 5/group) treated with vehicle (10 days), ACTZ (10 days), HCTZ (4 days), and pretreatment with ACTZ (6 days) and then treated with ACTZ/HCTZ for 4 days (10 days total) were subjected to balanced studies. Urinary sodium levels were determined for urine samples collected on the final day of the study for each group. Animals were euthanized. Blood samples and kidneys and were collected from each animal. Serum samples were analyzed for blood urea nitrogen. <b>a. Body weights.</b> Daily weight monitoring in animals before and after the initiation of ACTZ treatment with or without HCTZ indicates that rats treated with ACTZ plus HCTZ lost weight compared to rats on ACTZ alone. ACTZ treated animals (no HCTZ) showed comparable body weight gain to vehicle treated animals (Results). <b>b. Salt excretion.</b> Sodium excretion was ∼1.45 mEq/24 hrs in vehicle treated, 1.9 mEq/24 hrs in ACTZ and 2.6 mEq/24 hrs in ACTZ + HCTZ-treated groups. * indicates significant difference (see text for more information). <b>c. Expression of renin in kidneys of Vehicle-, HCTZ-, ACTZ- and ACTZ/HCTZ-treated animals.</b> The mRNA expression and protein levels of renin (left and right panels) were measured by Northern Hybridization and Western Blot in kidneys of control and animals that were treated with ACTZ, HCTZ or ACTZ plus HCTZ. Results shown are representative of 2 separate studies examining 4 different rats from each treatment group. <b>d. BUN levels in Vehicle-, HCTZ-, ACTZ- and ACTZ/HCTZ-treated animals.</b> BUN concentration levels were measured in animals treated with ACTZ, HCTZ or both. <b>e. Systemic acid base parameters.</b> Animals treated with ACTZ + HCTZ have significantly elevated arterial blood bicarbonate levels and pH compared to other experimental groups.