A reliable method for generating antibodies against pancreozymin, secretin and gastrin.

High specific antibodies against the gastrointestinal hormones pancreozymin, secretin, and gastrin were generated by coupling these peptides with N,N'-carbonyldiimidazole to bovine serum albumin. None of the antisera showed any cross reaction with gut and pancreatic hormones tested for cross reactivity. The dilution of antisera which were useful for the detection of 5-250 pg of hormone in human serum were 1:150 000 for secretin, 1:2000 for gastrin, and 1:2000 for pancreozymin. The N,N'-carbonyldiimidazole reagent is therefore highly effective for binding labile peptides to protein carriers without destroying the immunogenic features.