RELATIONSHIP BETWEEN GONADOTROPIN INHIBITORY HORMONE (GNIH) AND FEEDING RELATED HORMONES IN THE CICHLID FISH CICHLASOMA DIMERUS

BRECCIA, ANDRÉS; SALLEMI JULIETA; VISSIO, PG; SOMOZA GM; DI YORIO, MP

Mar del Plata

Congreso; REUNIÓN ANUAL DE LAS SOCIEDADES DE BIOCIENCIAS; 2023

Sociedad Argentina de Biología

Gonadotropin inhibitory hormone (Gnih) is a neuropeptide that inhibitsthe reproductive axis in birds and mammals. In recent years,Gnih has also been shown to be involved in the regulation of feedingand the control of energy homeostasis in these groups. In teleostfishes, a growing number of studies demonstrate that Gnih regulatesreproductive function; however, there are few studies linking Gnih tofeeding and nutritional status in this group. In our laboratory, preliminaryresults showed that four weeks of fasting conditions induceda significant decrease in Gnih mRNA levels in the hypothalamusof the cichlid fish Cichlasoma dimerus. Taking into account our results,we proposed that Gnih could act as a link between feedingand reproduction. Therefore, this work aimed to study the anatomicalrelationships between Gnih producing neurons and those thatproduced the main hypothalamic hormones involved in feedingcontrol, proopiomelanocortin (Pomc), and neuropeptide Y (Npy) inC. dimerus. Adults were sampled, and the brains were dissectedand processed for double-immunofluorescence. By double immunofluorescence,we found a close association between Npy-immunoreactive(-ir) somata and Gnih-ir fibers in the nucleus posteriorperiventricularis of the hypothalamus, as well as fiber-fiber closeassociations along the ventral hypothalamus. With respect to Pomcirneurons, we observed fiber-somatic and fiber-fiber contacts withGnih-ir fibers in the nucleus lateralis tuberis as well as fiber-fibercontacts in the preoptic area. We also found that Npy-ir fibers arein close contact with Pomc-ir somata and its fibers. No differenceswere observed between males and females. In conclusion, to ourknowledge, this is the first study performed in a teleost fish to show amorphological association between Gnih, Pomc, and Npy, providingevidence that this neuroendocrine network may be conserved alongthe vertebrate lineage.