[Dosage dependence of the effect of somatostatin on human splanchnic blood flow]

The effect of three different doses of somatostatin on splanchnic blood flow (SBF) and on arterial plasma insulin, glucagon and glucose was determined. 125, 250 and 500 microgram/h of somatostatin was infused during 60 minutes in 3 groups of 6 patients undergoing arterial-hepatic-venous catheterization; no patient had clinical evidence of metabolitic or hepatic disease. Continuous infusion of 125 microgram/h somatostatin was without significant effect on SBF, whereas 250 microgram/h resulted in a mean 28% reduction of SBF (p less than 0.05). Doubling the dose to 500 microgram/h affected SBF similarly (21% reduction of SBF). In contrast, administration of all three doses of somatostatin suppressed the circulating insulin and glucagon levels significantly. In a recent report somatostatin had been administered in a dose of 250 microgram/h to control gastric ulcer hemorrhage. The present studies demonstrate that this dose results in a significant reduction of SBF which cannot be further depressed by increasing the dose.