Influence of gastrointestinal hormones on tumor microcirculation of experimental pancreatic cancer in the rat

Background/Aims: Gastrointestinal hormones influence the microcirculation i n the normal pancreas. In the present study, we studied the effect of cerul ein and somatostatin on pancreatic cancer microcirculation after orthotopic and nonorthotopic tumor implantation, Methods: In 36 male Lewis rats (150- 180 g) induction of a ductlike pancreatic cancer was achieved by intrapancr eatic or intraperitoneal tumor fragment interposition between two inert tra nsparent polymethyl methacrylate plates. After 4 weeks, intravital microsco py of the tumor microcirculation was performed in a temperature-controlled immersion chamber. The animals received 5 mu g/kg cerulein or 3 mg/kg somat ostatin for 1 h intravenously. The erythrocyte velocity in normal pancreati c capillaries or in tumor vessels was measured, Results: The erythrocyte ve locity in the capillaries of the normal pancreas was 1.01 +/- 0.11 mm/s at baseline and increased to 1.64 +/- 0.09 mm/s after cerulein stimulation (p = 0.007). Pancreatic cancer vessels demonstrated no increase in erythrocyte velocity after orthotopic (baseline 0.95 +/- 0.14 mm/s, after 1 h 0.86 +/- 0.13 mm/s; n.s.) and nonorthotopic tumor implantation (baseline 0.91 +/- 0 .12 mm/s, after 1 h 0.95 +/- 0.14 mm/s; n.s.) after cerulein stimulation. S omatostatin decreased the erythrocyte velocity both in normal pancreas (bas eline 0.87 +/- 0.02 mm/s, after 1 h 0.60 +/- 0.07 mm/s; p = 0.01) and in pa ncreatic cancer (baseline 0.85 +/- 0.20 mm/s, after 1 h 0.63 +/- 0.18 mm/s; p = 0.02) after orthotopic tumor implantation. There was no effect of soma tostatin after nonorthotopic tumor implantation (baseline 0.90 +/- 0.10 mm/ s, after 1 h 0.88 +/- 0.14 mm/s; n.s.). Conclusion: These data suggest that pancreatic cancer microcirculation lacks physiological blood flow control by stimulatory hormones, in contrast to the normal pancreas. Copyright (C) 2000 S. Karger AG, Basel.