Secretin: A new role for an old hormone.

Plasma-secretin levels were measured by radioimmunoassay during a 72-hour starvation period in nine healthy subjects. Immunoreactive secretin (I.R.S.) levels rose dramatically during starvation. The rises were several orders of magnitude greater than those after intraduodenal acid. The classic concept that the major function of secretin is the control of the exocrine pancreas is challenged by these results. The findings suggest that secretin is a hormone of importance during starvation, and its role in starvation may be related to its lipolytic properties.