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Titolo:
Intrarenal renin-angiotensin system contributes to tubular acidification adaptation following uninephrectomy
Autore:
Amorena, C; Damasco, C; Igarreta, P; MacLaughlin, M;
Indirizzi:
Univ Buenos Aires, Fac Med, Inst Invest Cardiol, RA-1122 Buenos Aires, DF,Argentina Univ Buenos Aires Buenos Aires DF Argentina RA-1122 s Aires, DF,Argentina Univ Buenos Aires, Fac Ciencias Exactas & Nat, Dept Quim Biol, PHROM,CONICET, RA-1122 Buenos Aires, DF, Argentina Univ Buenos Aires Buenos Aires DF Argentina RA-1122 Aires, DF, Argentina
Titolo Testata:
EXPERIMENTAL NEPHROLOGY
fascicolo: 1, volume: 9, anno: 2001,
pagine: 60 - 64
SICI:
1018-7782(2001)9:1<60:IRSCTT>2.0.ZU;2-J
Fonte:
ISI
Lingua:
ENG
Soggetto:
NA+-H+ EXCHANGE; PROXIMAL TUBULE; CONVERTING ENZYME; DIETARY-PROTEIN; REMNANT KIDNEY; SALINE LOAD; RAT; REABSORPTION; TRANSPORT; SODIUM;
Keywords:
converting enzyme; uninephrectomy; renin-angiotensin system; angiotensin; proximal tubular acidification; micropuncture; Na+-H+;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Life Sciences
Citazioni:
40
Recensione:
Indirizzi per estratti:
Indirizzo: MacLaughlin, M Univ Buenos Aires, Fac Med, Inst Invest Cardiol, Marcelo T Alvear 2270, RA-1122 Buenos Aires, DF, Argentina Univ Buenos Aires Marcelo T Alvear 2270 Buenos Aires DF Argentina RA-1122
Citazione:
C. Amorena et al., "Intrarenal renin-angiotensin system contributes to tubular acidification adaptation following uninephrectomy", EXP NEPHROL, 9(1), 2001, pp. 60-64

Abstract

Background/Aims: Reduction in renal mass by uninephrectomy induces a functional compensation in the remnant kidney. The activity of the angiotensin-converting enzyme (ACE) as well as renin mRNA in the proximal convoluted tubule (PCT) of uninephrectomized (UNx) rats increases. The aim of this work was to determine whether the increased activity of the local renin-angiotensin system (RAS) participates in the adaptation of renal function after uninephrectomy. Method: We utilized normal two-kidney (2K) and 3-week UNx rats to study the activity of the ACE in vesicles obtained from luminal membranes of proximal tubular cells and the acidification kinectics in PCTs using micropuncture techniques. Results: The converting enzyme activity was significantly larger in UNx (5.87 +/- 0.69 nmol.min(-1).mg protein(-1)) than in 2K rats (2.43 +/- 0.13 nmol.min(-1).mg protein(-1); p < 0.05). The acidification rate constant (kappa) in PCT of 2K rats was 0.18 +/- 0.02 s(-1) and inUNx rats 0.30 +/- 0.04 s(-1) (p < 0.001). In UNx rats, microperfusion with10(-5) M ramipril or 10(-5) M losartan decreased kappa to 0.19 +/- 0.02 and 0.18 +/- 0.02 s(-1), respectively, but had no effect on 2K rats. Luminal steady-state pH (pH(infinity)) was the same in 2K and UNx rats, and was notmodified by addition of 10(-5) M ramipril or 10(-5) M losartan in both groups. The proximal H+ flux (J(H+),), calculated from pH(infinity), and kappa, was 1.12 nmol.cm(-2).s(-1) in 2K rats and, 1.77 nmol.cm(-2).s(-1) in UNx rats (p < 0.001). In 2K rats, this value was not changed by 10(-5) M ramipril or 10(-5) M losartan, but in UNx rats J(H+) decreased 25 and 30% with ramipril or losartan, respectively (p < 0.001). Conclusions: These data suggest that the increase in the local RAS activity could be an adaptive change that contributes to maintain the homeostasis of body fluids after uninephrectomy. Copyright (C) 2000 S. Karger AG, Basel.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 27/01/20 alle ore 01:26:19