Release of somatostatin-like immunoreactivity from the lower gut

The present study describes the effect of the instillation of a nutrient-containing hyperosmolar volume load into the lower ileum upon plasma levels of somatostatin-like immune-reactivity. The baseline levels of SLI in the mesenteric vein were significantly higher than those in the inferior vena cava and rose significantly in both veins in response to the nutrient load. SLI levels in the venous effluent of the pancreas and stomach did not rise. Mesenteric vein SLI was similar in molecular size to the SLI in the gastric and pancreatic veins and to synthetic somatostatin. The results suggest that the lower gut may contribute to the basal circulating SLI levels and that it is released from the lower gut in response to a nutrient-containing hyperosmolar volume load.