TOVAR MO, GÁRRIZ A, MENÉNDEZ-HELMAN R, DEL FRESNO P, MIRANDA LA, SOMOZA GM. Effects of estrogens in environmentally relevant concentrations on kiss2 and kiss2rb expression in pejerrey fish brain, pituitary and testes. SETAC Latin America 11th Biennial

TOVAR MO; GARRIZ A; DEL FRESNO P; MENÉNDEZ-HELMANN RJ; SOMOZA, GUSTAVO,; MIRANDA LA

Buenos Aires

Congreso; SETAC Latin America 11th Biennial; 2015

SETAC

Environmentalestrogenic compounds can interfere with the endocrine system and adversedevelopmental and reproductive effects in animals. Estradiol (E2) and 17α-ethynylestradiol (EE2) contributeto the estrogenic activity in water bodies all over the world. During the lastyears, a more inclusive concept has emerged: neuroendocrine disruption, inorder to include the full breadth of integrative physiology. So, we aimed tostudy the neuropeptide kisspeptin (kiss), known to control reproductivefunction in vertebrates. For example, in Daniorerio and Carassius auratus kisspeptinmRNA expression in the brain is increased after E2 treatments and putativebinding sites for estrogen receptors (ERs) have been characterized in kisspeptinand kisspeptin (kissr) receptorpromoter regions. In most teleost species, the kisspeptin system is composed bytwo ligands (kiss1 and kiss2) and two receptors (kiss2rb and kiss3rb); and it is known that kiss2/kiss2rbare related to gonadal maturation. In this context, the main of the presentstudy was to evaluate the effects of E2, EE2 and their mixture on kiss2/kiss2rb mRNA expression in theBrain-Pituitary-Testicular axis of pejerrey. To accomplish this goal, five adultmales were maintained in 60 L tanks during 14 days, using a static exposuresystem (by duplicates). Fish were exposed to 350 ng/L of E2 and 45 ng/L of EE2,and the mixture of both estrogens at the same concentrations, and the steroidswere added every two days in order to keep their concentration constant. At theend of the exposure, fish were anesthetized and sacrificed. A brain section (fromthe optic tectum to the inferior lobe of the hypothalamus), the pituitary glandand the testes were dissected, total RNA obtained and cDNA was synthetized byreverse transcription reaction. Kiss2and kiss2rb expression was measuredby RT-qPCR, using ß-actin and elongation factor 1 as reference genes. The estrogensmixture induced a rise of kiss2 and kiss2rb mRNA expression in the brain, comparedto the other treatments. No significant differences in kiss2 or kiss2rb levelswere observed in the pituitary gland and testes. These results suggest thatestrogenic compounds have a differential action on kiss2/kiss2rb expressiondepending on the tissue and show,that kisspeptin is a target of endocrine disruption. Further studies must bedone to clarify this action, probably mediated by ER response elements inpejerrey as it has already been reported for other teleost.