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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.
C Bertuccio, and
F R Ibarra, and
O Pignataro, and
J Toledo, and
E Arrizurieta, and
R S Martín
January 1993,
Experimental nephrology,
C Bertuccio, and
F R Ibarra, and
O Pignataro, and
J Toledo, and
E Arrizurieta, and
R S Martín
September 1993,
Pflugers Archiv : European journal of physiology,
C Bertuccio, and
F R Ibarra, and
O Pignataro, and
J Toledo, and
E Arrizurieta, and
R S Martín
August 1985,
The American journal of pathology,
C Bertuccio, and
F R Ibarra, and
O Pignataro, and
J Toledo, and
E Arrizurieta, and
R S Martín
June 1988,
Pflugers Archiv : European journal of physiology,
C Bertuccio, and
F R Ibarra, and
O Pignataro, and
J Toledo, and
E Arrizurieta, and
R S Martín
April 1988,
Proceedings of the National Academy of Sciences of the United States of America,
C Bertuccio, and
F R Ibarra, and
O Pignataro, and
J Toledo, and
E Arrizurieta, and
R S Martín
January 2001,
American journal of physiology. Renal physiology,
C Bertuccio, and
F R Ibarra, and
O Pignataro, and
J Toledo, and
E Arrizurieta, and
R S Martín
October 1987,
The Journal of clinical investigation,
C Bertuccio, and
F R Ibarra, and
O Pignataro, and
J Toledo, and
E Arrizurieta, and
R S Martín
September 2004,
American journal of physiology. Renal physiology,
C Bertuccio, and
F R Ibarra, and
O Pignataro, and
J Toledo, and
E Arrizurieta, and
R S Martín
August 1986,
The American journal of physiology,
C Bertuccio, and
F R Ibarra, and
O Pignataro, and
J Toledo, and
E Arrizurieta, and
R S Martín
September 1992,
The American journal of physiology,
