Distribution of insulin binding sites on Leydig cells of rat testes using insulin-coated gold particles |
| |
Authors: | M Kimura A Lukinius J L E Ericsson L Grimelius |
| |
Institution: | (1) Department of Anatomy, Aichi Medical University, Nagakute-cho, 480-11 Aichi, Japan;(2) Department of Pathology, University of Uppsala, University Hospital, S-751 85 Uppsala, Sweden |
| |
Abstract: | Summary The distribution of insulin binding sites in Leydig cells dispersed with collagenase from rat testes was studied using insulin-coated gold particles as an electron opaque ligand. Using electron microscope is convenient to distinguish Leydig cells among a variety of cells in crude preparations by their ultrastructural characteristics. Leydig cells were shown to possess insulin-binding sites on their plasma membranes. Initial binding sites of insulin were located to the microvillous surfaces. Following binding, receptor-ligand complexes seemed to move to the intermicrovillous plasma membrane, then to be internalized. Two modes of the internalization were confirmed. Most of the receptor-ligand complexes on Leydig cells appeared to be internalized via large, uncoated plasma membrane invaginations, while the remainder became internalized via small pits into vesicles. The receptor-ligand complexes were subsequently transferred to large subsurface vacuoles with electron-lucent lumens believed to correspond to endosomes. The reason why IGCs on the postendosomal pathway moving toward lysosomes was also discussed. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|