Receptor-mediated internalization of LHRH antagonists by pituitary cells
| Autor: | Yitzhak Koch, Dana Keinan, R. Meidan, Eli Hazum, Mordechai Liscovitch, Hans R. Lindner |
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| Rok vydání: | 1983 |
| Předmět: |
endocrine system
medicine.medical_specialty media_common.quotation_subject Receptors Cell Surface Peptide Biology Gonadotropic cell Biochemistry Gonadotropin-Releasing Hormone Structure-Activity Relationship Endocrinology Internal medicine medicine Animals Receptor Internalization Molecular Biology media_common chemistry.chemical_classification Rats Inbred Strains Receptor-mediated endocytosis Luteinizing Hormone Rats Cell biology Endocytic vesicle Microscopy Fluorescence chemistry Hormone receptor Pituitary Gland Female Luteinizing hormone Receptors LHRH hormones hormone substitutes and hormone antagonists |
| Zdroj: | Molecular and Cellular Endocrinology. 30:291-301 |
| ISSN: | 0303-7207 |
| DOI: | 10.1016/0303-7207(83)90065-5 |
| Popis: | A fluorescently labeled antagonist of luteinizing hormone releasing hormone (LHRH), d -pGlu- d -Phe- d -Trp-Ser-Tyr- d -Lys6-(tetramethylrhodamine)-Leu-Arg-Pro-Gly-NH2, was prepared. This peptide retained high-affinity binding to the LHRH receptor of pituitary plasma membrane preparations. The analog was able to block LHRH-stimulated LH release from pituitaries incubated in vitro, and exhibited minor agonistic activity. This rhodamine-labeled antagonist was utilized for the microscopic visualization and localization of LHRH receptors in dispersed rat pituitary cells. The fluorescently labeled receptors were initially distributed uniformly on the cell surface. The hormone-receptor complexes were redistributed after incubation at 23 °C and formed clusters which subsequently became internalized (at 37°C) into endocytic vesicles. Addition of LHRH (10-6 M) abolished these processes, indicating specific binding sites for the rhodamine-labeled peptide to the gonadotrope cells, A quantitative comparison of temperature-dependent internalization by iodinated LHRH agonist and antagonist revealed that both analogs were internalized to a similar extent. These findings suggest that LHRH-receptor complex internalization is related to LHRH receptor regulation. |
| Databáze: | OpenAIRE |
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