Importance of liver interstitial pressure on sodium retention.
Experiments were performed on 23 dogs to assess the effect of splanchnic pooling on renal hemodynamics and Na retention. When the thoracic duct pressure was raised to 40 cm H2O (HTDP), liver interstitial pressure rose from 9.0 +/- 0.4 to 19.8 +/- 1.1 cm H2O. Simultaneously, glomerular filtration rate (GFR) and renal plasma flow fell in the left kidney from 16.3 +/- 1.7 to 9.6 +/- 1.3 and from 73.7 +/- 12.2 to 44.3 +/- 9.8 ml.min-1, respectively (p less than 0.01). UNa.V fell to 59 +/- 9% of control value (p less than 0.01). Plasma antidiuretic hormone (ADH) rose from 29.5 +/- 7.7 to 46.9 +/- 9.2 pg.ml-1 (p less than 0.05). When a portocaval shunt (PCS) was opened in 10 dogs during HTDP after the first set of experimental measurements, splanchnic pressure fell from 17.2 +/- 1.1 to 11.5 +/- 1.2 cm H2O, attended by a return towards control of GFR. ADH fell significantly to 16.5 +/- 8.1 during PCS, and to 9.7 +/- 1.5 pg.ml-1 during a last, postexperimental control period. Instead, UNa.V remained unchanged at the low levels measured during HTDP alone. When the HTDP was released in the 17 dogs without, and the 10 dogs with PCS, all variables became indistinguishable from control, except for UNa.V, which remained reduced, even in 4 aldosterone-escaped animals. No significant change in any of these variables occurred in 6 sham-operated control animals. These data demonstrate that it is possible to increase interstitial liver pressure through the lymph duct.(ABSTRACT TRUNCATED AT 250 WORDS)