Stereospecificity of the effects of ozolinone on renal hemodynamics and on segmental tubular sodium reabsorption in conscious rats |
| |
Authors: | M Shalmi J S Petersen S Christensen |
| |
Institution: | Department of Pharmacology, University of Copenhagen, Denmark. |
| |
Abstract: | The study was performed to elucidate the effects of the two stereoisomers of ozolinone (d,l) on renal hemodynamics and proximal tubular Na reabsorption. Clearance experiments were performed in conscious water-loaded female Wistar rats. The clearances of 3H]inulin, 14C]tetraethylammonium and lithium were used as estimates for glomerular filtration rate, renal plasma flow and delivery of fluid from the proximal tubules, respectively. When the baseline parameters had stabilized, d- or l-ozolinone was injected i.v. in doses of 4, 20 and 100 mg/kg. 1-Ozolinone caused a transient and dose-dependent diuretic-natriuretic response with no evidence of a ceiling. At peak natriuresis, 2.5-5 min after 100 mg/kg of 1-ozolinone, the fractional Na excretion was increased from 0.5 to 25%; this was associated with an increased fractional excretion of lithium from 27 to 60%, and small transient decreases of renal hemodynamic parameters. d-Ozolinone had no significant effects except for a small natriuresis after 100 mg/kg. It is concluded that in water-loaded conscious rats 1-ozolinone is a powerful diuretic which, in contrast to d-ozolinone, increases the delivery of fluid from the proximal tubule as judged from changes in lithium clearance. |
| |
Keywords: | |
|
|