Previous investigations showed that nifedipine limited calcium phosphate stone formation induced by a high-cholesterol diet in rats. This study was performed to obtain further insights into the effects of nifedipine on stone prevention, renal function and urine composition. Male Wistar rats were assigned to one of the following groups: (1) cholesterol diet (n = 22), (2) cholesterol diet plus nifedipine (n = 22) and (3) control (n = 6). A high-cholesterol diet was given for 4 weeks, nifedipine was administered by gavage to group 2 for 4 weeks (50 mg/kg/24 h). During weeks 1 and 4, 5 rats of each group were housed in metabolic cages for urine collection. Sodium (Na), calcium (Ca), magnesium (Mg), phosphate (Pi), citrate and creatinine were determined in the urine. The kidneys of 4 animals of group 1 and 2 were perfused and removed for histology after 1,2,3 and 4 weeks, respectively. Clearance studies (inulin, Na, Ca, Mg, Pi) were performed (n = 6/group) after 4 weeks. The cholesterol diet induced a marked renal stone formation which was significantly limited by nifedipine [calcification index (week 4) 1.75 ± 0.5 vs. 0.75 ± 0.5]. The sequential histological examinations showed that concrement formation started intracellularly after only 1 week in group 1 whereas in group 2 the first concretions were observed only after 3 weeks. The cholesterol diet induced an increased excretion of Ca and Pi, citrate and Mg were reduced. The concomitant application of nifedipine resulted in a higher excretion of Ca, Mg and citrate when compared to the cholesterol group. The inulin clearance was decreased in the latter group. Nifedipine limited this decrease. The fractional excretion (FE) of Ca, Pi and Mg was increased with the cholesterol diet. Nifedipine further increased the FE of Ca and Mg; FE of Pi was decreased when compared to group 1. Our results show that nifedipine limits nephrolithiasis and the deterioration of renal function in rats fed a cholesterol diet. Tubular cells obviously play a key role in the process of cholesterol-induced stone formation, probably being more important than changes in urine composition.

Keywords:
Nifedipine, Nephrolithiasis, Nephrocalcinosis, Urolithiasis, Cholesterol, Renal function
This content is only available via PDF.
© 1994 S. Karger AG, Basel
1994
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.