title: Cytochemical characterization of pituitary target cells for biotinylated gonadotropin releasing hormone.
abstract: These studies describe the application of new cytochemical stains that co-localize a biotin-labeled gonadotropin releasing hormone (GnRH) analog and FSH or LH in the same field or cell. Pituitary monolayer cells were stimulated with the [D-Lys6] GnRH analog or the same analog labeled with biotin. Biotinylated [D-Lys6] GnRH exhibited a higher affinity and was 7-10 X more potent than unlabeled [D-Lys6] GnRH. The avidin-biotin peroxidase complex technique (ABC) was applied to localize the biotinylated GnRH on the cells with the use of a dense black peroxidase substrate. Specificity tests showed that the stain could be eliminated by competition with unlabeled [D-Lys6] GnRH. The GnRH stain was followed by immunocytochemical stains for LH beta, FSH beta or 25-39ACTH with a different peroxidase substrate (amber or orange-red). Stain for GnRH was found on the surfaces of 16% of the cells and 60-90% of the GnRH stained cells also stained for one of the gonadotropins. Most (90-100%) of the gonadotropes showed stain for GnRH. Our studies demonstrate that a potent biotinylated GnRH analog binds cells that can be identified specifically as gonadotropes.
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000494:pharmacology; D007700:Kinetics; D007986:Luteinizing Hormone / Q000378:metabolism; D010902:Pituitary Gland / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011966:Receptors, LHRH
chemical_list: D011956:Receptors, Cell Surface; D011966:Receptors, LHRH; D007987:Gonadotropin-Releasing Hormone; C035029:LHRH, Lys(6)-; C039935:LHRH, biotin-Lys(6)-; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone