title: Seasonal effect of GnIH on gonadotrope functions in the pituitary of goldfish.
abstract: Gonadotropin-inhibitory hormone (GnIH) inhibits gonadotropin release in birds and mammals. To investigate its role in teleosts, we examined the effects of synthetic goldfish (g)GnIH on pituitary LH-β and FSH-β subunit, and gGnIH receptor (gGnIH-R) mRNA levels and LH secretion in goldfish. Intraperitoneal injections of gGnIH increased pituitary LH-β and FSH-β mRNA levels at early to late gonadal recrudescence, but reduced serum LH and pituitary gGnIH-R mRNA levels, respectively, at early to mid-recrudescence and later stages of recrudescence. Static incubation with gGnIH elevated LH secretion from dispersed pituitary cell cultures from prespawning fish, but not at other recrudescent stages; suppressed LH-β mRNA levels at early recrudescence and prespawning but elevated LH-β at mid-recrudescence; and consistently attenuated FSH-β mRNA in a dose-specific manner. Results indicate that in goldfish, regulation of LH secretion and gonadotropin subunit mRNA levels are dissociated in the presence of gGnIH and dependent on maturational status and administration route.
authors.affiliation: Department of Biological Sciences, University of Calgary, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Moussavi
authors.forename: M
authors.initials: M
authors.lastname: Wlasichuk
authors.forename: J P
authors.initials: JP
authors.lastname: Chang
authors.forename: H R
authors.initials: HR
authors.lastname: Habibi
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D005260:Female; D029941:Fish Proteins / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D037201:Follicle Stimulating Hormone, beta Subunit / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D006054:Goldfish; D052681:Gonadotrophs / Q000378:metabolism / Q000502:physiology*; D006066:Gonads / Q000502:physiology; D007028:Hypothalamic Hormones / Q000494:pharmacology / Q000502:physiology*; D037101:Luteinizing Hormone, beta Subunit / Q000097:blood / Q000235:genetics / Q000378:metabolism; D008297:Male; D010902:Pituitary Gland / Q000166:cytology* / Q000378:metabolism; D061251:Primary Cell Culture; D060888:Real-Time Polymerase Chain Reaction; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism; D055703:Reproductive Physiological Phenomena; D012621:Seasons; D014158:Transcription, Genetic
chemical_list: D029941:Fish Proteins; D037201:Follicle Stimulating Hormone, beta Subunit; D007028:Hypothalamic Hormones; D037101:Luteinizing Hormone, beta Subunit; D011956:Receptors, Cell Surface