Rat pancreatic hydrolases from birth to weaning and dietary adaptation after weaning.

KoRBERECHT, P., M. DESCHODT-LANCKMAN, J. CAMUS, J. BRUYLANDS, AND J. CHRISTOPHE. Rat pancreatic hydrolases from birth to weaning and dietary adaptation cfter weaning. Am. J. Physi~l. 221(l): 376-381. 197 1 .-Within 2-4 days after birth, there was a marked depletion of cr-amylase and chymotrypsinogen in the rat pancreas. During the period 14-2 1 days, a-amylase, lipase, trypsins, and chymotrypsin increased in the small intestine, the three first corresponding levels of (pro) enzymes in the pancreas doing the same, but less evidently. After weaning (21 days) enzyme activities in the pancreas were modified by the nature of the diet. Amylase was markedly augmented by increasing the dietary intake of starch, lipase by lard, and trypsinogens by casein. The most important modifications, already manifested after 2 days, were a twofold increase in the specific activity of amylase on starch diet and a fourfold increase in the specific activity of lipase and trypsinogens, on lard and casein diets, respectively. Comparison of enzyme activities in pancreas and in small and large intestines indicates that rates of biosynthesis and secretion were not the sole factors determining intestinal activities in weanling rats. This was confirmed by a study of the in vitro stability of hydrolases in the washings of the small intestine, indicating that the stability of trypsins and amylase was reduced by 4 days of high-casein or high-lard diets. L