The influence of nutrition on the formation of amylase and lipase secretion and homeostasis in the pancreas of rats of various ages during postnatal ontogenesis

The present study investigated the influence of dietary macronutrient composition on the postnatal development of pancreatic amylase and lipase activities in male outbred rats. Animals were maintained after weaning on one of four diets—control mixed feed plus carrots, carbohydrate-enriched (combined feed and bread), lipid-enriched (combined feed, bread and butter), or protein-enriched (combined feed and cooked egg white)—and enzyme activities were measured in pancreatic homogenate and serum at six ages (15 days, 1 month, 1.5 months, 2 months, 3 months and 4 months). In the control group both enzyme activities increased with age, with amylase rising more steeply than lipase and reaching maximal values at 4 months. The carbohydrate-enriched diet accelerated the rise in pancreatic and serum amylase activity from one month of age (relative increases of 13.6–20.8 %). The lipid-enriched diet selectively accelerated lipase activity from two months of age (relative increases of 9–28.5 %). The protein-enriched diet elevated both amylase and lipase activities at most ages examined, consistent with a broader stimulatory effect on acinar-cell protein synthesis. Strong positive correlations between tissue and serum activities (r = 0.41–0.99 for amylase; r = 0.57–0.94 for lipase) supported coordinated enzyme release into the circulation. These findings demonstrate that dietary composition modulates the age-dependent formation of amylolytic and lipolytic activity homeostasis in the pancreas and blood during postnatal ontogenesis, with protein-rich feeding exerting the most general effect on enzyme development. Keywords: amylase, lipase, postnatal ontogenesis, homeostasis, pancreas, diet adaptation