Influence of hydrocortisone on the development of pancreas in suckling rats. Ultrastructural morphometric and biochemical studies.

The effect of hydrocortisone on the growth and differentiation of the pancreas was examined in suckling rats. Three doses of hydrocortisone (40, 20, 5 mg/kg/day) were administered during the second week of life. Biochemical and ultrastructural morphometric studies were performed on the pancreas at the end of the treatment. Whatever the dose used, hydrocortisone induced pancreatic hypertrophy and significantly increased enzymatic activities by 70-200% for lipase and colipase, 140-340% for trypsinogen and chymotrypsinogen and 600-1,200% for amylase. With the 20-mg/kg/day dose, ultrastructural morphometric data indicated that the increase in pancreatic weight was associated with cellular exocrine hypotrophy (diminution of cell size, and of the number of zymogen granules). They also suggest that hydrocortisone, at that dose, might enhance the excretion of secretory products. By contrast, the 5-mg/kg/day dose of hydrocortisone did not modify the acinar cell size, but significantly increased the number of granules per cell. The increase in pancreatic weight and the fact that either cellular hypotrophy or no change in acinar cell size was observed, strongly suggest that hyperplasia occurred with both doses. These results confirm that hydrocortisone is an important modulator of pancreatic development in the rat, inducing stimulation of pancreatic activities, associated with modifications in cell structure and components which vary according to the dose.