Saraux B, Girard-Globa A
J Dev Physiol. 1982 Apr;4(2):121-37.
Pancreatic amylase, chymotrypsinogen, lipase and colipase were assayed, at intervals, in rats from day 16 of fetal life until weaning. In the fetus, amylase and chymotrypsinogen accumulated regularly, in parallel, until birth. Lipase and colipase accumulation slowed down between day 20 and birth. The ratio of colipase to lipase was extremely high (9.5) and decreased until weaning towards adult values. Enzyme contents of the pancreas were depleted after birth and remained low until day 14. Intestinal concentrations were equally low, showing that pancreatic depletion was not due to hypersecretion. Protein synthesis was very active, intermediate between that of the fetus and of the adult. It is concluded that in the early suckling phase the proteins synthesized are mainly constitutive and not enzymatic. Starvation followed by refeeding showed that secretion sensitivity to nutritional stimulation only appears at 14 days. During the suckling period amylase concentrations decreased, evidencing a degree of nutritional sensitivity to the low level of carbohydrate in the diet. The productive capacity for lipase underwent a slow maturation which was not even complete at weaning, since concentrations had not yet reached adult level despite the high fat content of milk. This was in part compensated for by the high proportion of colipase but shows that lipase was not adaptative during this phase and that pancreatic lipase can hardly account for lipid digestion before weaning.
从胎儿期第16天到断奶期间，定期检测大鼠胰腺中的淀粉酶、胰凝乳蛋白酶原、脂肪酶和辅脂酶。在胎儿期，淀粉酶和胰凝乳蛋白酶原平行且有规律地积累，直至出生。脂肪酶和辅脂酶的积累在第20天至出生期间减缓。辅脂酶与脂肪酶的比例极高（9.5），并逐渐下降，直至断奶时接近成年水平。出生后胰腺中的酶含量减少，直到第14天一直保持在低水平。肠道中的酶浓度同样很低，这表明胰腺中酶含量的减少并非由于分泌过多所致。蛋白质合成非常活跃，介于胎儿和成年期之间。由此得出结论，在早期哺乳阶段，合成的蛋白质主要是组成型的，而非酶类。饥饿后再喂食的实验表明，对营养刺激的分泌敏感性直到第14天才出现。在哺乳期间，淀粉酶浓度下降，这表明对饮食中低水平碳水化合物存在一定程度的营养敏感性。脂肪酶的生产能力经历了缓慢的成熟过程，甚至在断奶时仍未完成，因为尽管乳汁中脂肪含量高，但脂肪酶浓度尚未达到成年水平。这在一定程度上由高比例的辅脂酶所补偿，但表明在此阶段脂肪酶不具有适应性，并且在断奶前胰腺脂肪酶几乎无法解释脂质消化过程。
