Pepperberg D R, Okajima T L, Ripps H, Chader G J, Wiggert B
Lions of Illinois Eye Research Institute, Department of Ophthalmology and Visual Sciences, University of Illinois, College of Medicine, Chicago 60612.
Photochem Photobiol. 1991 Dec;54(6):1057-60. doi: 10.1111/j.1751-1097.1991.tb02129.x.
It has been hypothesized that interphotoreceptor retinoid-binding protein (IRBP) functions as a two-way carrier of retinoid between the retinal pigment epithelium (RPE) and rod photoreceptors in the vertebrate eye. This hypothesis has been tested in recent studies that have employed purified, initially ligand-free, bovine IRBP and the "RPE-eyecup" obtained from the toad (Bufo marinus) eye. The present experiments further characterize the IRBP/RPE-eyecup system with respect to (i) the solubilization and protection of retinol by IRBP, and (ii) the time course of IRBP-mediated release of 11-cis retinal by the RPE. The data, together with previous findings in the IRBP/RPE-eyecup preparation, support the view that 11-cis retinal is the principal retinoid released by the RPE into IRBP-supplemented aqueous medium, and that IRBP in vivo promotes the regeneration of rhodopsin by facilitating the exchange of retinoid between bleached rods and the RPE.
据推测，光感受器间类视黄醇结合蛋白（IRBP）在脊椎动物眼中作为视网膜色素上皮（RPE）和视杆光感受器之间类视黄醇的双向载体发挥作用。这一假说在最近的研究中得到了验证，这些研究使用了纯化的、最初不含配体的牛IRBP以及从蟾蜍（海蟾蜍）眼睛获得的“RPE眼杯”。本实验进一步就以下方面对IRBP/RPE眼杯系统进行了表征：（i）IRBP对视黄醇的溶解和保护作用，以及（ii）IRBP介导RPE释放11-顺式视黄醛的时间进程。这些数据，连同之前在IRBP/RPE眼杯制剂中的发现，支持了以下观点：11-顺式视黄醛是RPE释放到添加了IRBP的水性介质中的主要类视黄醇，并且体内的IRBP通过促进漂白视杆和RPE之间类视黄醇的交换来促进视紫红质的再生。
