GnRH in the invertebrates: an overview

Abstract

Publisher Summary This chapter provides an overview of GnRH in the invertebrates. The gonadotropin-releasing hormone (GnRH), which was previously called luteinizing hormone-releasing hormone (LHRH), represents a pivotal peptide in animal reproduction. GnRH is a decapeptide originally isolated from the porcine and ovine hypothalamus and is characterized for its ability to enhance the release of pituitary gonadotropins, follicle-stimulating hormone (FSH), and luteinizing hormone (LH). All known forms of GnRH peptides have in common a pyroglutamyl residue at the amino terminus and an amidated glycine at the carboxy terminus. Except for the octoGnRH, all other known forms are decapeptides and differ by one or more amino acids; amino acids 4 and 9 are conserved in all forms known to date. Studies involving an evolutionary approach to GnRH have adopted one particular strategy; attention is on understudied invertebrate taxonomic groups. Invertebrate species that vary in their phylogenetic relationships are likely to reveal differences, as well as similarities, in GnRH form and function. Studies on invertebrate species are beginning to provide further insights on the structural and functional similarities and differences. The perspective that evolution has acted to shape the GnRH molecule effectively leads to investigations in a comparative approach.