Effect of testosterone on carbonic anhydrase and MG(2+)-dependent HCO3-stimulated ATPase activities in rat kidney: comparison with estradiol effect.
Effects of testosterone administration (TP; 1-3 mg/kg body weight, S.C., once daily for 7 days) on the cytosol carbonic anhydrase (CA) and tubular brush border Mg(2+)-dependent HCO3(-)-stimulated ATPase (Mg(2+)-HCO3(-)-ATPase) activities of normal and castrated male and female rat kidney were compared with estradiol (E2) effects. TP decreased kidney CA activity in a dose-dependent manner in all four animal conditions, and negative correlations were observed between cytosol CA activity and serum testosterone concentration. However, brush border Mg(2+)-HCO3(-)-ATPase activity was not affected by testosterone. Orchiectomy increased only CA activity and its value recovered to normal levels by 3 mg/kg TP replacement, whereas Mg(2+)-HCO3(-)-ATPase activity did not change. In the previous study, on the other hand, E2 administration activated both kidney enzymes in normal male rats and only Mg(2+)-HCO3(-)-ATPase in normal female rats. Testosterone and E2 conversely affected kidney CA activity in male rats. These facts suggest that the cytosol CA may control kidney functions on H+ and HCO3- metabolism under the balance of both sex hormones in the living body.
Suzuki
S
S
Department of Pharmacology, Kanazawa Medical University, Ishikawa, Japan.
Yoshida
J
J
Takahashi
T
T
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D001639:Bicarbonates / Q000378:metabolism*; D002256:Carbonic Anhydrases / Q000378:metabolism*; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D007668:Kidney / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D008274:Magnesium / Q000502:physiology*; D008297:Male; D009919:Orchiectomy; D009929:Organ Size / Q000187:drug effects; D010052:Ovariectomy; D011506:Proteins / Q000378:metabolism; D011863:Radioimmunoassay; D051381:Rats; D017208:Rats, Wistar; D013739:Testosterone / Q000494:pharmacology*
D001639:Bicarbonates; D011506:Proteins; D013739:Testosterone; D004958:Estradiol; D000251:Adenosine Triphosphatases; D002256:Carbonic Anhydrases; D008274:Magnesium