Expression and Activation of Gonadotropin Receptors

Among the many hormones that are produced by the anterior pituitary gland, luteinizing hormone (LH, lutropin), follicle-stimulating hormone (FSH, follitropin), and thyroidstimulating hormone (TSH, thyrotropin) form the separate family of so-called glycoprotein hormones (reviewed by Oharib el al., 1990). These hormones consist of two glycosylated subunits, a and p, which are associated through non-covalent interactions. The a-subunit is identical for all glycoprotein hormones, whereas the p-subunit is hormone specific. The gonadotropins, LH and FSH, are the key regulators of testis and ovary function, and are synthesized in cells called the gonadotrophs of the pituitary gland. TSH, which regulates thyroid function, is produced in the thyrotrophs. In primates and horses, a fourth glycoprotein hormone exists, chorionic gonadotropin (CO), which is synthesized in the placenta during pregnancy, and is structurally and functionally related to LH (Oharib el al., 1990)

Regulation of gonadotropin receptor gene expression

The receptors for the gonadotropins differ from the other G protein-coupled receptors by having a large extracellular hormone-binding domain, encoded by nine or ten exons. Alternative splicing of the large pre-mRNA of approximately 100 kb can result in mRNA species that encode truncated receptor proteins. In this review we discuss the regulation of gonadotropin receptor mRNA expression and the possible roles of alternative splicing in gonadotropin receptor function

Alternative splicing of follicle-stimulating hormone receptor pre-mRNA: cloning and characterization of two alternatively spliced mRNA transcripts

Glycoprotein hormone receptors contain a large extracellular domain that is encoded by multiple exons, facilitating the possibility of expressing alternatively spliced transcripts. We have cloned two new splice variants of the rat follicle-stimulating hormone (FSH) receptor gene: FSH-R1 and FSH-R2. The splice variant FSH-R1 differs from the full-length FSH receptor mRNA by the inclusion of a small extra exon between exons 9 and 10. FSH-R2 lacks the first three base pairs o