The endometrium cycle involves proliferation of endometrial epithelial cells in preparation for implantation of fertilized ovum. With ovulation, the endometrium secretes nutrients such as peptides and amino acids into the endometrial cavity. The histological evidence of ovulation in normal menstrual cycle includes subnuclear glycogen vacuoles surrounded by placental leucine aminopeptidase (P-LAP) in endometrial epithelial cells. P-LAP is an essentially involved in intracellular trafficking of glucose transporter (GLUT) 4 which is primarily important for glucose uptake in skeletal muscles and fat tissues. On the other hand, glucose influx from blood into endometrial epithelial cells is not mainly mediated by GLUTs, but by coincident appearing progesterone just after ovulation. Progesterone increases permeability of not only plasma membranes, but also lysosomal membranes, and this may be primarily involved in glucose influx. Progesterone also expands the exocytosis in the endometrium after ovulation, and endometrial secretion after ovulation is possibly apocrine and holocrine, which is augmented and exaggerated exocytosis of the lysosomal contents. The endometrial spiral arteries/arterioles are surrounded by endometrial stromal cells which are differentiated into decidual/pre-decidual cells. Decidual cells are devoid of aminopeptidase A (APA), possibly leading to enhancement of Angiotensin-II action in decidual cell area due to loss of its degradation by APA. Angiotensin-II is thought to exert growth-factor-like effects in post-implantation embryos in decidual cells, thereby contributing to implantation. Without implantation, angiotensin-II constricts the endometrial spiral arteries/arterioles to promote menstruation. Thus, P-LAP and APA may be involved in homeostasis in uterus via regulating glucose transport and vasoconstrictive peptides.

中文翻译：

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在植入和月经方面对人子宫内膜氨基肽酶的新见解。

子宫内膜周期涉及子宫内膜上皮细胞的增殖，以准备受精卵的植入。随着排卵，子宫内膜将营养物质（例如肽和氨基酸）分泌到子宫内膜腔中。正常月经周期中排卵的组织学证据包括子宫内膜上皮细胞中被胎盘亮氨酸氨基肽酶（P-LAP）包围的亚核糖原液泡。P-LAP实质上参与了葡萄糖转运蛋白（GLUT）4的细胞内运输，葡萄糖转运蛋白4对于骨骼肌和脂肪组织中的葡萄糖摄取至关重要。另一方面，葡萄糖从血液中流入子宫内膜上皮细胞的途径主要不是由GLUT介导，而是在排卵后同时出现孕激素。孕酮不仅增加质膜的通透性，而且还包括溶酶体膜，这可能主要与葡萄糖流入有关。孕酮还会在排卵后扩大子宫内膜的胞吐作用，而排卵后的子宫内膜分泌物可能是顶泌碱和全泌尿激素，这会增加和夸大溶酶体成分的胞吐作用。子宫内膜螺旋动脉/小动脉被分化为蜕膜/蜕膜前细胞的子宫内膜基质细胞包围。蜕膜细胞中没有氨肽酶A（APA），可能会导致蜕膜细胞区域中血管紧张素II的作用增强，这是由于其被APA降解所致。据认为，血管紧张素-II在蜕膜细胞的植入后胚胎中发挥生长因子样作用，从而有助于植入。没有植入 血管紧张素II收缩子宫内膜螺旋动脉/小动脉以促进月经。因此，P-LAP和APA可能通过调节葡萄糖转运和血管收缩肽参与子宫的体内平衡。