Adaptive vasodilatory response after octreotide treatment

Despite the suppression of glucagon release, an adaptive response aimed at maintaining vasodilatation after octreotide treatment may exist in portal h ypertension. The present study was undertaken to evaluate the possible inte raction between endothelium and non-endothelium-derived vasodilators after 1-wk octreotide administration in cirrhotic rats. Rats were allocated to re ceive either vehicle or octreotide (30 or 100 mug/kg every 12 h subcutaneou sly). Hemodynamic values, plasma glucagon levels, endothelium-related vasod ilatory activities, and aortic endothelial nitric oxide synthase (eNOS) exp ression were determined after treatment. Octreotide administration decrease d plasma glucagon and increased serum 6-keto-PGF(1 alpha) and NOx levels wi thout affecting the hemodynamic values. In cirrhotic rats receiving octreot ide, there was a blunt response to either L-NAME or indomethacin administra tion alone, but this blunt pressor response disappeared after simultaneous administration of the two drugs. Additionally, an increased aortic eNOS exp ression was observed in cirrhotic rats receiving 1-wk octreotide. It is con cluded that 1-wk octreotide treatment did not correct the hemodynamic deran gement in cirrhotic rats. The enhanced endothelium-related vasodilatory act ivity was noted after octreotide treatment that overcame the octreotide-ind uced hemodynamic effects in portal hypertension.