title: Quantification of the effects of resperine on gonadotroph expression in the pituitary of goldfish (Carassius auratus).
abstract: In many teleosts, the control of gonadotropin II (or luteinizing hormone) secretion is under the dual control of stimulatory and inhibitory neuroendocrine factors. The principal stimulating factor is gonadotropin-releasing hormone and the main inhibitor is dopamine. Inhibiting the activities of dopamine by antidopaminergic drugs potentiates the actions of exogenous gonadotropin-releasing hormone analogs, resulting in a surge release of luteinizing hormone and ovulation and spawning in a number of different species. As the effects of blocking the inhibitory actions of dopamine on gonadotroph cytology have not been studied, goldfish were treated with 2, 4, 6 or 8 injections of reserpine (0.1 mg/kg body weight), at 48 h intervals, and the numbers of gonadotrophic cells studied at 48 h following last injection. After two injections, the number of gonadotrophic cells increased by 189% over controls; after four injections the increase was 234%; after six injections the increase was 259% and after eight injections, 288%. The results suggest that dopamine has an inhibitory influence on the numbers of gonadotrophs.
authors.affiliation: Unidad de Morfología y Función, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, AP 314, Tlalnepantla, Edo. de México, México 54090, México.
authors.forename: Gabriela A
authors.initials: GA
authors.lastname: Osornio
authors.forename: Monica
authors.initials: M
authors.lastname: Chavez
authors.forename: Richard E
authors.initials: RE
authors.lastname: Peter
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Cardenas
mesh_terms: D018759:Adrenergic Uptake Inhibitors / Q000008:administration & dosage*; D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D004298:Dopamine / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects; D006054:Goldfish / Q000502:physiology*; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism; D006066:Gonads / Q000502:physiology* / Q000648:ultrastructure; D007986:Luteinizing Hormone / Q000378:metabolism*; D008297:Male; D010902:Pituitary Gland / Q000378:metabolism*; D012110:Reserpine / Q000008:administration & dosage*
chemical_list: D018759:Adrenergic Uptake Inhibitors; D007987:Gonadotropin-Releasing Hormone; D012110:Reserpine; D007986:Luteinizing Hormone; D004298:Dopamine