The effects of intravenous infusion of solutions with different colloid osmotic pressures on rat mesenteric lymph pressure.
The effects of intravenous infusion of solutions of varied colloid osmotic pressure on mesenteric lymph pressure were measured by a glass micropipette. The lymph pressure was 4.0 +/- 1.6 cm H2O between the second and third valve of rat mesenteric lymphatic vessels with diameter of 101 +/- 25 micron (mean +/- SD). Intravenous infusion of 1 ml/100g body weight (B.W.) of isotonic saline, 5% glucose solution, and 20% glucose solution increased the lymph pressure by 1.6 +/- 0.5 cm H2O, 1.5 +/- 0.3 cm H2O and 2.0 +/- 1.0 cm H2O, respectively. Infusion of 2 ml/100g B.W. of the same solutions increased the lymph pressure by 3.3 +/- 1.3 cm H2O, 3.3 +/- 1.6 cm H2O and 3.7 +/- 0.8 cm H2O, respectively. Infusion of hydroxyethyl starch solution, with colloid osmotic pressure of 25 mmHg, minimally altered the lymph pressure. One ml/100g B.W. infusion of low molecular weight dextran solution, with colloid osmotic pressure of 162 mmHg, decreased the lymph pressure by 1.3 +/- 0.9 cm H2O, and 2 ml/100g B.W. infusion of this solution decreased the lymph pressure by 2.0 +/- 1.0 cm H2O. The different effects on lymph pressure derive from the differences in colloid osmotic pressure of these solutions in conformity with the Starling hypothesis.