The brain-pituitary axis structure in captivity reared females of Steindachneridion parahybae (Siluriformes).

HONJI, R.; CANEPPELE, D; PANDOLFI, M.; LO NOSTRO, F.; MOREIRA, R.

Cochin

Simposio; IX International Symposium on the Reproductive Physiology of Fish.; 2011

Background: Steindachneridion parahybae is a freshwater catfish, endemic to the Paraíba do Sul River Basin, Brazil, which has been seriously threatened by environmental disturbances in the last decades [1]. This species is in the conservation program undertaken by the Energetic Company of São Paulo State (CESP) that depends on the collection of wild broodstock and their transference to captivity for artificial reproduction. However, the domestication of this broodstock is not completely successful, because they exhibit reproductive impairments in captivity [2]. The endangered status and endocrine dysfunction showed by this species in captivity deserves special attention and urgent action addressing the knowledge of its reproductive physiology, which is the basic premise for fish restocking programs. Captivity negatively impacts on the brain-pituitary axis (BP), mainly on the gonadotropin-releasing hormone (GnRH) production, which is the main regulator of gonadotropins (GtHs): follicle-stimulating hormone (FSH) and luteinizing hormone (LH) release from pituitary. Although fish pituitary has been studied for many years [3], there is no information about the anatomy and pituitary cell types in Neotropical catfishes yet, mainly in species, which show reproductive dysfunctions in captivity. Thus, the BP axis structure and cytoarchitecture is the key to understand the physiological causes of reproductive dysfunctions; therefore, our studies focused on the GnRH neurons, FSH and LH cells in S. parahybae sexually mature females in