Cellular adaptation of the rat medullary thick ascending limb to chronic renal failure.
Medicina (B Aires)
; 55(4): 329-33, 1995.
Article
em En
| MEDLINE
| ID: mdl-8728873
Chronic renal failure (CRF) is accompanied by adaptive changes in renal and extrarrenal epithelial ionic transport. Fluid reabsorption in the thick ascending limb of Henle is increased and the capacity to lower the urine osmolality in water diuresis is preserved. To study the cellular mechanism of this adaptation, we measured intracellular cAMP in microdissected medullary thick ascending limb (mTAL) segments in rats with CRF. mTAL exhibited in CRF nephrons an increase of basal cAMP from 6.0 +/- 1.5 in controls to 47.0 +/- 10.3 fmol. mm-1 tubule in CRF (P < 0.05). Maximally stimulated cAMP levels (10(-3) M IBMX plus 10(-5) M Forskolin) were different from basal levels in controls (6.0 +/- 1.5 vs 63.1 +/- 18.8, P < 0.05) but not from basal levels in CRF (47.0 +/- 10.3 vs 63.0 +/- 16.0, P = N.S.). Preincubation with the adenylate cyclase inhibitor 2'5'-dideoxyadenosine (DDA) 10(-4) M produced no changes in cAMP in controls (93.7 +/- 10.3% of DDA untreated samples) whereas it decreased to 76.2 +/- 8.8% (24% inhibition) in CRF (P < 0.05). No differences between controls and CRF groups were found in basal and stimulated cAMP in red blood cells and distal colon. The data would suggest that the cAMP pathway is an intracellular signal for mTAL adaptation in epithelial transport and that the adenylate-cyclase system is specifically activated in CRF.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
AMP Cíclico
/
Falência Renal Crônica
/
Alça do Néfron
Limite:
Animals
Idioma:
En
Revista:
Medicina (B Aires)
Ano de publicação:
1995
Tipo de documento:
Article
País de afiliação:
Argentina
País de publicação:
Argentina