The localization of estrogen receptors on human osteoblasts: a preliminary optical and electron microscopic technique

Attempts to identify estrogen target cells in bone by immunocytochemistry using antibodies to the receptor have proved to be controversial. The aim of this study was therefore to determine whether immunogold labeling can be used as a technique for the localization of estrogen receptors (ER) on a human osteoblast-like cell line. The aim was also to determine the distribution of ER on the cell surface by using a scanning electron microscope (SEM) and intracellularly by using a transmission electron microscope (TEM). Labeling of the cytoplasmic material was seen around areas that appeared to be a disrupted plasma membrane. No nuclear or perinuclear labeling could be detected. The conclusion can be made that SEM immunogold labeling combined with TEM can be regarded as a practical technique for localizing ER on human osteoblasts. This article clearly demonstrated that osteoblast-like cells do express ER at low levels and that, although cytoplasmic immunoreactivity could be detected, no nuclear or perinuclear labeling was found.