Effect of chlorpropamide on water and urea transport in the inner medullary collecting duct
| Autor: | A S Rocha, Wong C. Ping, Lúcia H. Kudo |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Chlorpropamide
Osmosis Vasopressin medicine.medical_specialty Biological Transport Active chemistry.chemical_compound Internal medicine Renal medulla medicine Animals Urea Kidney Tubules Collecting Water transport Chemistry Water Rats Inbred Strains Water-Electrolyte Balance Diuresis Rats medicine.anatomical_structure Endocrinology Urea transport Mechanism of action Nephrology medicine.symptom Diabetes Insipidus Antidiuretic medicine.drug |
| Zdroj: | Kidney International. 39:79-86 |
| ISSN: | 0085-2538 |
| DOI: | 10.1038/ki.1991.10 |
| Popis: | Effect of chlorpropamide on water and urea transport in the inner medullary collecting duct. The present in vitro microperfusion study examined whether chlorpropamide (CPM) has a direct effect on hydraulic conductivity (Lp × 10-6 cm/atm · sec) and 14C-urea permeability (Pu × 10-5 cm/sec) in the middle and distal inner medullary collecting duct (IMCD) obtained from acutely water-loaded Wistar rats and rats homozygous for diabetes insipidus (DI). CPM (10-4M) added to the bath fluid increased the Lp in the water-loaded Wistar rats from -0.05 ± 0.13 to 6.25 ± 0.74 (p < 0.01) and in the DI rats from 0.05 ± 0.01 to 5.95 ± 0.84 (p < 0.01), but had no effect when it was added to the perfusate. CPM stimulated Lp in a dose-dependent manner with the threshold effect at 10-6 M. However, the addition of CPM (10-4 M) to submaximal concentration of VP in the bath fluid did not increase the Lp. Furthermore, CPM was unable to block the inhibitory action of PGE2 on the vasopressin (VP)-stimulated Lp. On the contrary, PGE2 blocked the CPM-stimulated Lp. CPM (10-4 M) in the peritubular fluid was able to cause a significant rise of the Pu from 13.5 ± 0.8 to 17.3 ± 1.0 reversibly, which represented 16% of maximum stimulated effect produced by 50 µU/ml of VP. Thus, pharmacological doses of CPM added to the peritubular side have a direct effect on terminal IMCD increasing water and urea permeability in the absence of VP, but this drug does not potentiate the VP-stimulated water transport in the IMCD. Our results were unable to confirm the hypothesis that CPM potentiates the VP-antidiuresis by the inhibition of PGE2 action in the rat IMCD. |
| Databáze: | OpenAIRE |
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