Title: The granin-derived peptide secretoneurin is a multifunctional reproductive hormone
Speaker: Dr. Vance Trudeau, University of Ottawa
Abstract: Multiple neurotransmitters and neuropeptides interact to control luteinizing hormone (LH) and follicle stimulating hormone (FSH) release from gonadotrophs in the anterior pituitary gland. The LH surge is essential for fertility as it triggers ovulation in females and sperm release in males. While it is well-established that gonadotropin-releasing hormone (GnRH) and/or kisspeptin are required for pulsatile and surge release of LH in mammalian species, their essentiality is challenged by studies in the USA and Japan showing knockouts in zebrafish and medaka do not block reproduction. In goldfish, we have discovered that secretoneurin a (SNa), a neuropeptide derived from secretogranin-IIa (SgII) processing, stimulates LH release in vivo and from dispersed pituitary cells in vitro. SN does not bind to the human GnRH receptor and can enhance LH release from mouse LbetaT2 cells. Knockout of SgII genes in zebrafish indicates that these genes are required for optimal reproduction. SgII knockout reduces all stereotypical courtship behaviours. Spawning success is partially rescued in SgII knockout fish following injection of SNa. The SN peptide sequence is conserved from lamprey to human, suggesting a broader importance of this peptide family. Supported by NSERC and uOttawa-Institute of Hydrobiology/Chinese Academy of Sciences collaborative grants.
