MIRANDA Leandro Andres
Effects of short periods of warm water ﬂ uctuations on reproductive endocrine axis of the pejerrey (Odontesthes bonariensis ) spawning
ELISIO M; CHALDE T; MIRANDA LA
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. A: COMPARATIVE PHYSIOLOGY.
Lugar: Amsterdan; Año: 2012 vol. 163 p. 47 - 47
The aim of this study was to assess ﬂ uctuations in daily water temperature in Chascomús Lagoon during one year, and to evaluate wheth er the highest temperature recorded during pejerrey spawnin g season can produce an endocrine disruption on brain pituitary gonads axis. Fish were subjected to daily temperature ﬂuctuations: 17 °C to 19 °C (reproductive control), 19 °C to 25 °C, and 19 °C to 27 °C. After 8 days, ten ﬁsh per treatment were sacri ﬁ ced and gene expression of gonadotropin-r eleasing hormone (GnRH -I, GnRH-II, GnRH-III ), gonadotropin subunits- β (FSH- β, LH-β), glycopr otein hormone- α ( GPH-α), gonad otropin receptors (FSH-R, LH-R ), and gonadal aromatase ( cyp19a1a) was analyzed. Also, plasma levels of sexual steroids and gonadal repro ductive status were studied. Fish exposed to high temperature ﬂuctuations quit spawning, presenting clear signs of gonadal regression. Fish recovered its spawnin g activity 11 weeks after heat treatment. At endoc rine level, GnRH-I and FSH- β in both sexes, LH-β and GPH- α in males and FSH-R, LH-R and cyp19a1a in females decreased signi ﬁcantly in treated ﬁ sh. Also, a strong reduction in plasma sex steroid levels was found for both sexes. This study demons trated that pulses of warm water in natural environment during pejerrey spawnin g season can disrupt all levels of the reproductive axis, impairing reproduction.