Effects of diuretics on calcium excretion and Ca2+-activated ATPase in rat kidney.
Effects of three diuretics on the urinary Ca2+ excretion and on the microsomal Ca2+-activated ATPase were examined in the rat kidney. Furosemide and bumetanide increased Na+, K+, and Ca2+ excretion in the rats. Acetazolamide increased Na+ and K+ excretion but not Ca2+. Urinary inorganic phosphate excretion was not affected during the administration of acetazolamide. It is suggested that acetazolamide inhibits Na+ transport without affecting Ca2+ reabsorption in the rat nephron. Microsomal ATPase of the rat kidney cortex was  stimulated by Ca2+ or Mg2+ alone and an additive effect of the two cations was not observed. Microsomal ATPase activated by Ca2+ or Mg2+ was not inhibited by furosemide, bumetanide, and acetazolamide. These data suggest that the inhibitory effect of furosemide and bumetanide on the Ca2+ reabsorption is not related to the inhibition of Ca2+-activated ATPase.
D000086:Acetazolamide / Q000494:pharmacology; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D002034:Bumetanide / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism / Q000652:urine*; D004232:Diuretics / Q000494:pharmacology*; D004789:Enzyme Activation; D005665:Furosemide; D007668:Kidney / Q000201:enzymology*; D008274:Magnesium / Q000378:metabolism; D008297:Male; D008634:Mersalyl / Q000494:pharmacology; D008861:Microsomes / Q000201:enzymology; D010710:Phosphates / Q000378:metabolism; D011188:Potassium / Q000378:metabolism; D051381:Rats; D012964:Sodium / Q000378:metabolism
D004232:Diuretics; D010710:Phosphates; D002034:Bumetanide; D008634:Mersalyl; D005665:Furosemide; D012964:Sodium; D000251:Adenosine Triphosphatases; D008274:Magnesium; D000086:Acetazolamide; D011188:Potassium; D002118:Calcium