Dopamine inhibits luteinizing hormone synthesis and release in the juvenile European eel: a neuroendocrine lock for the onset of puberty.

• Published in: Biology of Reproduction
• Main Authors: Vidal, Bernadette, Pasqualini, Catherine, Le Belle, Nadine, Holland, M Claire H, Sbaihi, Miskal, Vernier, Philippe, Zohar, Yonathan, Dufour, Sylvie
• Other Authors: Biologie des organismes marins et écosystèmes (BOME), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN), Développement, évolution et plasticité du système nerveux (DEPSN), Centre National de la Recherche Scientifique (CNRS), Institut de Neurobiologie Alfred Fessard (INAF), Biotechnology Institute, University of Maryland Baltimore County (UMBC), University of Maryland System-University of Maryland System
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2004
• Subjects: MESH: Animals; MESH: Biometry; MESH: Genitalia; MESH: Gonadotropin-Releasing Hormone; MESH: Gonadotropins; MESH: Liver; MESH: Luteinizing Hormone; MESH: Neurosecretory Systems; MESH: Organ Size; MESH: Ovary; MESH: Pimozide; MESH: Pituitary Gland; MESH: Body Weight; MESH: Puberty; MESH: Testosterone; MESH: Tyrosine 3-Monooxygenase; MESH: Brain; MESH: Dopamine; MESH: Dopamine Antagonists; MESH: Eels; MESH: Endocrine Glands; MESH: Female; MESH: Gastrointestinal Tract; [SDV.NEU]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC]; Anguilla anguilla
• Online Access: https://hal.archives-ouvertes.fr/hal-00121615; https://doi.org/10.1095/biolreprod.104.030627

In various adult teleost fishes, LH ovulatory peak is under a dual neurohormonal control that is stimulatory by GnRH and inhibitory by dopamine (DA). We investigated whether DA could also be involved in the inhibitory control of LH at earlier steps of gametogenesis by studying the model of the European eel, Anguilla anguilla, which remains at a prepubertal stage until the oceanic reproductive migration. According to a protocol previously developed in the striped bass, eels received sustained treatments with GnRH agonist (GnRHa), DA-receptor antagonist (pimozide), and testosterone (T) either alone or in combination. Only the triple treatment with T, GnRHa, and pimozide could trigger dramatic increases in LH synthesis and release as well as in plasma vitellogenin levels and a stimulation of ovarian vitellogenesis. Thus, in the prepubertal eel, removal of DA inhibition is required for triggering GnRH-stimulated LH synthesis and release as well as ovarian development. To locate the anatomical support for DA inhibition, the distribution of tyrosine hydroxylase (TH) in the brain and pituitary was studied by immunocytochemistry. Numerous TH-immunoreactive cell bodies were observed in the preoptic anteroventral nucleus, with a dense tract of immunoreactive fibers reaching the pituitary proximal pars distalis, where the gonadotrophs are located. This pathway corresponds to that mediating the inhibition of LH and ovulation in adult teleosts. To our knowledge, this is the first demonstration of a pivotal role for DA in the control of LH and puberty in a juvenile teleost. These data support the view that DA inhibition on LH secretion is an ancient evolutionary component in the neuroendocrine regulation of reproduction that may have been partially maintained throughout vertebrate evolution.