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[Pituitary glycoprotein hormone receptors]
M Misrahi1, N Ghinea, M T Vu Hai
1Institut National de la Santé et de la Recherche Médicale, Hôpital de Bicêtre, Le Kremlin-Bicêtre.
Annales D'Endocrinologie
|January 1, 1995
Summary
Researchers characterized the porcine LH receptor, identifying its structure and variant forms. Studies revealed novel ovarian zonation and localized human receptor genes, advancing reproductive biology research.
Area of Science:
- Endocrinology and reproductive biology
- Molecular and cellular biology
- G protein-coupled receptor (GPCR) research
Context:
- The luteinizing hormone (LH) receptor plays a critical role in reproductive functions.
- Understanding its structure and expression is key to deciphering hormonal signaling pathways.
- Previous research lacked detailed characterization of the LH receptor's molecular forms and gene localization.
Purpose:
- To clone and characterize the porcine LH receptor.
- To investigate alternative splicing variants and physiological expression forms.
- To determine the chromosomal localization of human LH, FSH, and TSH receptor genes.
Summary:
- Monoclonal antibodies enabled cloning of the porcine LH receptor mRNA. Its structure reveals similarities and differences with other GPCRs, notably a large extracellular domain. Variant forms, including truncated species due to alternative splicing, were identified.
- Three physiologically expressed LH receptor forms were characterized: mature 85kDa transmembrane, 68kDa precursor, and 45-48kDa truncated variants. Novel ovarian zonation was observed via immunocytochemistry.
- The TSH receptor was isolated from human thyroid tissue. Human LH/FSH receptor genes map to chromosome 2p21, and the TSH receptor gene to 14q31. These large genes contain introns primarily in the 5' region of the extracellular domain.
- Intracellular trafficking of the LH receptor in Leydig and transfected cells was studied using immunoelectron microscopy. Transendothelial transfer of hCG in testicular microvasculature was also investigated.
Impact:
- Provides a detailed molecular understanding of the LH receptor, crucial for reproductive endocrinology.
- Identifies novel receptor variants and expression patterns, offering new targets for therapeutic interventions.
- Establishes precise gene localizations for human LH, FSH, and TSH receptors, aiding in genetic studies and disease research.
- Elucidates intracellular transport mechanisms and microvascular interactions, relevant for drug delivery and understanding hormone action.