Immunohistologic and Histologic Evidence that Follicle-Stimulating Hormone and Luteinizing Hormone Are Present in the Same Cell Type in the Human Pars Distalis
The human hypophyseal cells containing follicle stimulating hormone (FSH) and luteinizing hormone (LH) were identified immunohistologically by an immunoglobulin-peroxidase bridge procedure. Antisera to FSH and LH reacted selectively with their specific antigens in characterization studies employing radioactive binding analyses and the immunohistologic method after absorption with purified glycoprotein hormones. In serial immunostained sections, the same cells reacted with both gonadotropin antisera. Comparison of immunostained sections and serial sections stained with various cytologic coloration procedures showed that the cell type reactive with the gonadotropin antisera varied widely in staining. All remaining chromophilic cells were recognizable as producing pituitary hormones other than gonadotropins and were unreactive with gonadotropin antisera. The latter histologic finding supports the immunohistologic demonstration that FSH and LH are both found in a single cell population.The gonadotropic cells were small-to-medium sized cells, which usually occurred throughout the pars distalis in acini populated predominantly by other cell types. A new hypophyseal staining procedure, consisting of an alcian blue-periodic acid-silver-orange G sequence, best served to differentiate gonadotropic cells, and revealed that the cells often contained 2 apparently different granule types. The granules of gonadotropic cells appeared to be more susceptible than the granules of other cell types to destruction by autolysis or histologic staining procedures.