Ontogeny of two vitamin A-metabolizing enzymes and two retinol-binding proteins present in the small intestine of the rat.
Ontogeny of two vitamin A-metabolizing enzymes and two retinol-binding proteins present in the small intestine of the rat.
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发表时间：
1991-09
影响因子：
6.5
通讯作者：
D E Ong;Peter C. Lucas;B. Kakkad;Timothy C. Quick
中科院分区：
文献类型：
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作者：
D E Ong;Peter C. Lucas;B. Kakkad;Timothy C. Quick
检测围产期大鼠小肠细胞视黄醇结合蛋白（CRBP）、细胞视黄醇结合蛋白二型[CRBP（II）]、卵磷脂：视黄醇酰基转移酶（LRAT）和微粒体视网膜还原酶的表达模式。 CRBP 在最早检查时即妊娠第 16 天就存在（每毫克可溶性蛋白 15 pmole），出生时下降 70%，一直维持到成年。相比之下，CRBP(II)在出生前2-3天出现，在出生后第3天升至最高水平（500 pmole/mg可溶性蛋白），然后在哺乳后期下降50%至成年水平。免疫组织化学显示，CRBP(II) 最初以斑片状方式出现在上皮细胞层中，出生后就分解为所有绒毛相关肠上皮细胞的均匀染色。相比之下，CRBP 在第 17/18 天时在上皮细胞层中均匀表达，但在出生时不表达。肠道LRAT活性在出生前2天内迅速增加，然后在断奶时下降至成年水平。出生时在肠道中可测量到微粒体视网膜还原酶，但在哺乳早期未检测到，在第 21 天再次出现。断奶时观察到微粒体视网膜还原酶显着增加，此时视黄醛的来源胡萝卜素成为维生素 A 的重要来源。这些元素的出现模式似乎为肠道为出生后所需的维生素 A 的必要加工做好了准备。
The patterns of expression of cellular retinol-binding protein (CRBP), cellular retinol-binding protein, type two [CRBP(II)], lecithin: retinol acyltransferase (LRAT), and microsomal retinal reductase were examined for rat small intestine during the perinatal period. CRBP was present (15 pmole per mg soluble protein) at the earliest time examined, the 16th day of gestation, declining by 70% by birth, maintained to adulthood. In contrast, CRBP(II) appeared 2-3 days before birth, rising to its highest level (500 pmole per mg soluble protein) by day 3 after birth, then declining by 50% during the late suckling period to the adult level. Immunohistochemistry revealed that CRBP(II) initially appeared in the epithelial cell layer in a patchy manner, resolving by birth into an even staining of all villus-associated enterocytes. In contrast, CRBP was evenly expressed in the epithelial cell layer at day 17/18 but was absent by birth. Intestinal LRAT activity increased rapidly in the 2 days prior to birth, then declined at weaning to the adult level. Microsomal retinal reductase was measurable in the intestine at birth, but not detected during the early suckling period, reappearing at day 21. Considerable increase was then observed coincident with weaning, when carotenes, from which retinal is derived, became an important source of vitamin A. The pattern of appearance of these elements appears to prepare the intestine for the necessary processing of vitamin A required after birth.