Hild-Petito S, Verhage H G, Fazleabas A T
Department of Obstetrics and Gynecology, University of Illinois, Chicago 60612-7313.
Biol Reprod. 1994 Apr;50(4):791-801. doi: 10.1095/biolreprod50.4.791.
The objective of this study was to determine the presence, regulation, and localization of specific receptors for insulin-like growth factor I (IGF-I) in primate reproductive tissues. Uteri were obtained from baboons either during the menstrual cycle, after ovariectomy with or without steroid treatments, or during early pregnancy (Days 18-60 postovulation [PO]). Placental and decidual tissues were collected from baboons during late pregnancy (Days 130-160). Localization of type I IGF receptor was determined by indirect immunocytochemistry (alpha IR3 antibody), and levels of type I IGF receptors were determined by affinity cross-linking and binding assays. Specific staining for type I IGF receptors was present in the membranes of glandular epithelial cells throughout the cycle and early pregnancy; however, there was a decrease in staining intensity by the late luteal phase and also throughout early pregnancy compared to the late follicular phase. Specific receptor staining was absent in stromal cells throughout the cycle. By Day 19 PO, stromal cells directly under the trophoblast were positive for type I IGF receptor, and an increase in stromal staining at the implantation site was observed as pregnancy proceeded. Stromal staining was apparent in non-implantation site tissue by Day 32 PO. Some placental villi showed positive receptor staining as early as on Day 18 PO, and an increase in the number of positive villi was apparent as pregnancy progressed. An 125I-IGF-I-protein complex of approximately 140,000 daltons, corresponding to the alpha subunit of the type I IGF receptor, was detected in endometrial, placental, and decidual membranes. The intensity of this signal was high in endometrium from the follicular phase, whereas low levels were detected in endometrium from the luteal phase. Throughout early pregnancy, alpha receptor subunit was present in placental and decidual membranes; alpha receptor subunit increased in placenta as pregnancy proceeded. An additional 125I-IGF-I-protein complex of 43,000 daltons, corresponding to IGF binding protein-1 (IGFBP-1), was present in decidual membranes and appeared to increase as pregnancy proceeded. Specific binding of 125I-IGF-I to placental membranes was displaced by unlabeled IGF-I and alpha IR3 antibody, whereas both unlabeled IGF-I and IGF-II competed equally for binding to decidual membranes. Scatchard analysis of 125I-IGF-I binding to placental membranes revealed a single class of high-affinity receptors (KD = 2.35 +/- 0.8 nM; mean +/- SEM).(ABSTRACT TRUNCATED AT 400 WORDS)
本研究的目的是确定灵长类动物生殖组织中胰岛素样生长因子I（IGF-I）特异性受体的存在、调节及定位。子宫取自狒狒，取材时间分别为月经周期期间、卵巢切除术后（有无类固醇处理）或妊娠早期（排卵后18 - 60天[PO]）。胎盘和蜕膜组织取自妊娠晚期（130 - 160天）的狒狒。通过间接免疫细胞化学法（αIR3抗体）确定I型IGF受体的定位，通过亲和交联和结合试验确定I型IGF受体的水平。整个周期及妊娠早期，腺上皮细胞膜上均有I型IGF受体的特异性染色；然而，与卵泡晚期相比，黄体晚期及整个妊娠早期染色强度降低。整个周期中基质细胞均无特异性受体染色。排卵后第19天，滋养层下方直接接触的基质细胞I型IGF受体呈阳性，随着妊娠进展，着床部位的基质染色增加。排卵后第32天，非着床部位组织也出现基质染色。一些胎盘绒毛早在排卵后第18天就显示出阳性受体染色，随着妊娠进展，阳性绒毛数量增加。在子宫内膜、胎盘和蜕膜中检测到一种约140,000道尔顿的125I-IGF-I-蛋白复合物，对应于I型IGF受体的α亚基。该信号强度在卵泡期子宫内膜中较高，而在黄体期子宫内膜中较低。整个妊娠早期，α受体亚基存在于胎盘和蜕膜中；随着妊娠进展，胎盘中的α受体亚基增加。蜕膜中还存在一种43,000道尔顿的额外125I-IGF-I-蛋白复合物，对应于IGF结合蛋白-1（IGFBP-1），且随着妊娠进展似乎增加。未标记的IGF-I和αIR3抗体可取代125I-IGF-I与胎盘膜的特异性结合，而未标记的IGF-I和IGF-II对与蜕膜的结合竞争能力相同。对125I-IGF-I与胎盘膜结合的Scatchard分析显示存在一类高亲和力受体（KD = 2.
