The binding of oestradiol‐17ß to human spermatozoa — an electron microscope autoradiographic study

Abstract
The location of steroid binding sites with specificity for oestradiol-17ß at an ultrastructural level has been examined on human spermatozoa by electron microscope autoradiography. About 75% of the 438 grains produced by 3H-oestradiol-17ß, and counted on electron microscope autoradiographs, were found over the plasma membrane or within 1000 Å of it. This study provides evidence suggesting that the plasma membrane is a site of action of oestradiol-17β in human spermatozoa.