HEMODYNAMIC-EFFECTS OF OCTREOTIDE IN PORTAL HYPERTENSIVE RATS RECEIVING PROPRANOLOL

Background: The aim of this study was to investigate short-term effect s of propranolol (a non-selective beta-adrenergic antagonist), octreot ide (a long-acting somatostatin analogue), or a combination of these s ubstances on splanchnic and systemic haemodynamics and arterial blood gases in rats with portal vein stenosis. Methods: Splanchnic and syste mic haemodynamics were measured using the radioactive microspheres met hod. Eight rats first received an i.v, infusion of isotonic saline (10 mu L/min for 15 min) and then an i.v. infusion of octreotide (8 mu g. h/kg for 15 min). Eight other rats first received a bolus i.v. injecti on of propranolol (2 mg) and an i.v. infusion of octreotide 15 min lat er. Results: Propranolol or octreotide alone significantly decreased p ortal pressure (both by 23%), portal tributary blood now (35 and 10%, respectively) and cardiac index (36 and 26%, respectively). Octreotide administration in rats pretreated with propranolol significantly decr eased cardiac index but did not change portal and arterial pressures o r portal tributary blood flow. Propranolol significantly increased art erial oxygen tension. Octreotide alone or combined with propranolol si gnificantly decreased oxyhaemoglobin saturation and pH and increased c arbon dioxide tension. Conclusions: In rats with portal vein stenosis, the somatostatin analogue, octreotide, accentuates the short-term dec rease in cardiac index due to propranolol. In addition, octreotide alt ered arterial blood gases and acid-base status. In contrast, octreotid e does not further decrease portal pressure in animals receiving propr anolol.