Weaver L T, Gonnella P A, Israel E J, Walker W A
Harvard Medical School, Boston, Massachusetts.
Gastroenterology. 1990 Apr;98(4):828-37. doi: 10.1016/0016-5085(90)90004-k.
Epidermal growth factor may play an important part in postnatal gastrointestinal development. However, little is known of its role prenatally. The aim of this study was to detect epidermal growth factor in amniotic fluid and to study its uptake and transfer across the epithelium of fetal rat small intestine. Anesthetized 20-day gestation rats underwent caesarean section. Three fetuses were exteriorized, their abdomens were opened, and ligated loops of proximal and distal small intestine were infused with 100 micrograms epidermal growth factor. Infused segments were removed 30 min later and processed for electron microscopy, and tissue was embedded in LR gold resin. Sections were treated with rabbit anti-rat epidermal growth factor antibody, followed by 5 nm gold-labeled goat anti-rabbit immunoglobulin before staining. Epidermal growth factor was measured in amniotic fluid by radioimmunoassay. In the proximal and distal small intestine epidermal growth factor was found membrane-associated along the luminal surface of microvilli, within apical invaginations and endosomal compartments, free from the membrane in multivesicular bodies, within large clear vesicles, basal vesicles and in association with the basolateral membrane and beyond. Epidermal growth factor was found in amniotic fluid at a concentration of 0.38 +/- 0.07 (SD) ng/ml. This study shows that epidermal growth factor is present in amniotic fluid and is transported across the epithelium of fetal rats by an endocytotic process in both the upper and lower small intestine. It is likely that amniotic fluid epidermal growth factor plays a part in intestinal mucosal development, and may be active systemically after transepithelial passage in utero.
表皮生长因子可能在出生后胃肠道发育中起重要作用。然而，其在产前的作用却知之甚少。本研究的目的是检测羊水表皮生长因子，并研究其在胎鼠小肠上皮细胞的摄取和转运。对妊娠20天的大鼠进行麻醉后行剖宫产术。取出3只胎儿，打开其腹部，向近端和远端小肠的结扎肠袢注入100微克表皮生长因子。30分钟后取出注入段，进行电子显微镜处理，组织包埋于LR金树脂中。切片先用兔抗大鼠表皮生长因子抗体处理，然后在染色前用5纳米金标记的山羊抗兔免疫球蛋白处理。采用放射免疫分析法测定羊水中的表皮生长因子。在近端和远端小肠中，表皮生长因子沿微绒毛腔面与膜相关，存在于顶端内陷和内体区室，在多囊泡体中与膜分离，存在于大的清亮囊泡、基底囊泡中，并与基底外侧膜相关及超出该范围。羊水中表皮生长因子的浓度为0.38±0.07（标准差）纳克/毫升。本研究表明，表皮生长因子存在于羊水中，并通过内吞过程在胎鼠小肠的上段和下段上皮细胞中转运。羊水表皮生长因子可能在肠黏膜发育中起作用，并且在子宫内经上皮转运后可能具有全身活性。
