Secretin snuff: evaluation of the action on pentagastrin-stimulated gastric acid secretion and on pancreatic bicarbonate production.

In an informative qualitative study 75 U (near the range of 1 U/kg) secretin given as a snuff resulted in a weak but significant stimulation of pancreatic bicarbonate output in 8 volunteers studied. The result further indicated that this dose would slightly inhibit pentagastrin-stimulated gastric acid secretion. This was confirmed in a quantitative study at the dose of 150 U (similar to 2 U/kg), and the mean amount of inhibition of MAO was 30% in the 10 subjects studied. A supramaximal dose of 1 mg (approximatively 54 U/kg) of synthetic secretin given to one volunteer resulted in a transient block of near maximally pentagastrin-stimulated gastric acid secretion. The amount of acid inhibition as compared to a control experiment was 45% in the first and 52% in the two post-secretin hours. These results indicate that secretin given as a snuff at dose levels that would induce maximal pancreatic secretion when given as an i.v. injection results only in a weak inhibition of stimulated gastric acid secretion and evokes only a little stimulation of pancreatic bicarbonate secretion. Supramaximal secretin snuff doses have, however, a potent effect on both gastric and pancreatic secretion that is of similar order to that achieved by intravenous secretin. Owing to the obviously incomplete absorption of secretin through the nasal mucosa, secretin snuff is unlikely to solve the therapeutic problem of duodenal ulcer disease. If, however, an active fragment of the peptide could be synthetized at a reasonable price, the greater convenience of pernasal application might compensate for the partial loss of action.