STIMULATION OF PANCREATIC GROWTH BY SECRETIN AND CAERULEIN IN SUCKLING RATS

The current study examines the effects of secretin and caerulein alone, and in combination, on pancreatic growth. Six day old rats were injected every 12 hr for 5 days with either saline, secretin (25 /sag/kg), caerulein (1 pg/kg), or a combination of the above doses of secretin and caerulein. Alone, secretin produced hyperplasia and hypertrophy of the pancreatic tissue, as DNA contents and ratios of RNA, amylase and chymotrypsin to the former were significantly increased over control values. Caerulein, alone, was associated with pancreatic hyperplasia as DNA contents only were significantly increased over control values. Data suggest that atrophy resulted from the decapeptide treatment as most of the indices of hypertrophy are lower than the control values. The combination of secretin and caerulein also produced hyperplasia but caerulein reduced the hypertrophic effect of secretin. In conclusion, at doses identical to those given to adult rats, secretin produces hyperplasia and hypertrophy ofthe neonatal rat pancreas while caerulein initiates only hyperplasia. The response to secretin given alone is comparable to that previously reported in adult rats, but the response to caerulein is different, since in adult animals it was also associated with hypertrophy of the pancreatic tissue.