Repositorio UV :: Examinando por Autor "Directora de tesis: Whitlock, Kathleen"

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Alternate signalling pathways in the endocrine control of reproduction in zabrafish (Danio rerio)
(Universidad de Valparaíso, 2024) Mbar Tine, Eugene; Directora de tesis: Whitlock, Kathleen
Gonadotropin-releasing hormone (Gnrh) is a neuroendocrine decapeptide highly conserved across vertebrate species that is essential not only for the onset of puberty but also for the maintenance of reproductive state. Results from recent studies indicate that endogenous Gnrh does not control reproduction in zebrafish and potentially other fishes. Because fishes use waterborne hormones to control reproduction, we tested whether exogenous Gnrh affects the hypothalamic- pituitary axis. Gnrh introduced into water housing individual fish isolated from their conspecifics induced sex-specific pituitary responses on gonadotropins expression. Furthermore, blocking the noses eliminated these responses. To determine whether modulation of the exogenous Gnrh signalling pathway is controlled at the receptor level, a CRISPR/Cas9 loss of function mutant in the gonadotropin-releasing hormone receptor 3 (gnrh-receptor3) gene was generated. The gnrh-r3-/- mutants are infertile where males do not produce sperm, and females produce few mature oocytes. The data presented here suggest that zebrafish have a potential olfactory–portal system that underlies neuroendocrine communication controlling reproduction.