Ugolev A M, De Laey P, Iezuitova N N, Rakhimov K R, Timofeeva N M, Stepanova A T
Ciba Found Symp. 1979(70):221-46. doi: 10.1002/9780470720530.ch13.
Advances in the study of membrane digestion are described which relate to techniques for the separation of the apical glycocalyx and the study of the distribution of enzymes between the latter and the cell membrane. The regulatory properties of brush border enzymes have been demonstrated. Membrane digestion by pancreatic enzymes adsorbed on the mucosal surface and by enteric enzymes predominates in early development, whereas intraluminal digestion develops during the transition to definitive (adult) nutrition. Substrate and other, non-substrate factors are involved in the regulation of intraluminal and membrane digestion in ontogeny. The importance of lipid components of the diet for the maintenance of proximal-distal gradients of enzyme activity in the small intestine during the transition from milk to adult nutrition is discussed. At this period of development hydrocortisone affects both the synthesis of enzymes and their incorporation into the enterocyte membrane. The inducibility of different enzymes is not identical. The hypothesis has been proposed that stress is one of the factors inducing or repressing the synthesis of brush border enzymes. These effects are mediated through the hypothalamus, adrenals, hypophysis and thyroid. The experimental findings demonstrate that various stressors are responsible for the induction of sucrase, maltases, gamma-amylase, peptidases and alkaline phosphatase, and for the repression of lactase in suckling rats.
本文描述了膜消化研究的进展，这些进展涉及顶端糖萼的分离技术以及酶在糖萼与细胞膜之间分布的研究。已证实刷状缘酶的调节特性。在早期发育过程中，吸附在粘膜表面的胰酶和肠酶引起的膜消化占主导地位，而腔内消化则在向确定（成人）营养过渡期间发展。底物和其他非底物因素参与个体发育过程中腔内消化和膜消化的调节。讨论了饮食中的脂质成分在从母乳到成人营养过渡期间对维持小肠中酶活性近端 - 远端梯度的重要性。在这个发育阶段，氢化可的松影响酶的合成及其并入肠细胞膜的过程。不同酶的诱导性并不相同。有人提出假说，应激是诱导或抑制刷状缘酶合成的因素之一。这些作用是通过下丘脑、肾上腺、垂体和甲状腺介导的。实验结果表明，各种应激源会导致乳鼠蔗糖酶、麦芽糖酶、γ -淀粉酶、肽酶和碱性磷酸酶的诱导以及乳糖酶的抑制。
