Morphological and functional alterations to a sub-group of regulatory peptides in human pancreas and intestine after jejuno-ileal bypass.

The effect of ileo-gastrostomy on insulin and cholecystokinin secretion and the endocrine cells containing cholecystokinin, somatostatin, motilin, secretin, neurotensin and enteroglucagon was studied. Fasting and postprandial plasma samples collected pre- and post-operation demonstrated significant changes in circulating insulin and cholecystokinin. Fasting and postprandial insulin levels decreased three months after ileo-gastrostomy (postprandial pre-operation 40 +/- 8 microU/ml compared to 15 +/- 24 microU/ml post-operation, P < 0.02). The postprandial levels of cholecystokinin were significantly increased (pre-operation 7.1 +/- 1.1 pg/ml compared to 12.2 +/- 1.7 pg/ml post-operation, P < 0.02). Quantification of the endocrine cell populations in the jejunum in-continuity three months after ileo-gastrostomy demonstrated an hyperplasia of cholecystokinin-, secretin-, gastric inhibitory polypeptide-, motilin- and somatostatin-containing cells. In samples of the ileum taken from within the bypass loop the neurotensin- and somatostatin-containing cells were unaffected while the enteroglucagon-containing cells were significantly increased in number. Ileo-gastrostomy resulted in significant alterations to the abundance of regulatory peptide-containing endocrine cells and to circulating levels of insulin and cholecystokinin. These changes are implicated in the dramatic weight loss associated with the operation.