AGE-DEPENDENT INFLUENCE OF OCTREOTIDE ON STIMULATED PANCREATIC GROWTHIN THE POSTNATAL-PERIOD OF RATS

Objective: To investigate the effect of long-acting octreotide (SMS 20 1-995) on the plasma growth hormone level in preweaning rats and to st udy the growth and composition of the exocrine pancreas in these rats after stimulation by caerulein- and camostate-induced endogenous chole cystokinin (CCK). Methods: Wistar rats of both sexes were treated as l ittermate pairs in two periods of postnatal age, from days 1 to 11 and from days 11 to 21. To stimulate pancreatic growth, caerulein (3 mu g /kg subcutaneously three times daily) was given from days 1 to 11, and oral camostate (200 mg/kg given once daily) or CCK-8 (10 mu g/kg subc utaneously three times daily) was administered from days 11 to 21. Oct reotide (6 or 15 mu g/kg subcutaneously twice daily) was administered alone or in combination with caerulein or camostate. The rats were exs anguinated on days 11 or 21, and each pancreas was removed, weighed an d analysed. Results: Caerulein stimulated pancreatic growth and raised the trypsin concentration; camostate induced pancreatic hypertrophy a nd hyperplasia. By day 11, octreotide had decreased the plasma growth hormone level and the basal pancreatic trypsin concentration and conte nt. Given in combination with caerulein, octreotide reduced the growth hormone level and the stimulated trypsin and DNA contents. By day 21, rats treated with octreotide in the camostate group showed a reduced basal pancreatic trypsin concentration and a decreased basal trypsin c ontent (although the changes were not significant). Plasma growth horm one levels were not significantly reduced. Conclusion: The antitrophic pancreatic action of octreotide and its plasma growth hormone-lowerin g effect were shown in rats during the first 10 days after birth. Thes e effects were less notable from days 11 to 21, a period when CCK rece ptors increase in number and components of the stimulus-secretion mech anism are mature.