Excessive doses of cerulein stimulate pancreatic growth in suckling rats but damage the pancreas of weaned rats.

The cerulein-stimulated pancreatic growth response was evaluated in 4- and 11-day-old female suckling CFY rats and compared with the pancreatic response of cerulein-treated 24-day-old weaned rats. Cerulein was given subcutaneously in saline in 1-, 10- and 100-micrograms/kg doses t.i.d. The increase in pancreatic DNA content was regarded as an index for hyperplasia, and the increase in pancreatic weight, protein content and enzyme activity related to milligrams of DNA as an index for hypertrophy. Three-day administration of 1- and 10-micrograms/kg doses of cerulein increased the pancreatic trypsin/DNA ratio, and doses of 100 micrograms/kg cerulein evoked pancreatic hypertrophy and hyperplasia in 4-day-old rats. Ten-day administration of 1- and 10-micrograms/kg doses induced pancreatic hypertrophy and hyperplasia, while the 100-micrograms/kg doses induced pancreatic hypertrophy in 11-day-old rats. In 24-day-old weaned rats, the 3-day administration of 1-microgram/kg doses resulted in hypertrophy of the gland, while the 100-micrograms/kg doses of cerulein evoked pancreatic aplasia and atrophy. It is concluded that the growth-promoting effect of cerulein on the newborn rat pancreas is age- and dose-dependent.