Effects of short periods of warm water fluctuations on reproductive endocrine axis of the pejerrey (Odontesthes bonariensis) spawning

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• 作者：Mariano Elisio ; Tom¨¢s Chalde ; Le ; ro A. Mir ; a
• 关键词：Global warming ; Pejerrey ; Reproduction ; Sex hormones
• 刊名：Comparative Biochemistry and Physiology - Part A: Molecular & Integrative Physiology
• 出版年：2012
• 出版时间：September, 2012
• 年：2012
• 卷：163
• 期：1
• 页码：47-55
• 全文大小：2272 K

文摘

The aim of this study was to assess fluctuations in daily water temperature in Chascom¨²s Lagoon during one year, and to evaluate whether the highest temperature recorded during pejerrey spawning season can produce an endocrine disruption on brain-pituitary-gonads axis. Fish were subjected to daily temperature fluctuations: 17 ¡ãC to 19 ¡ãC (reproductive control), 19 ¡ãC to 25 ¡ãC, and 19 ¡ãC to 27 ¡ãC. After 8 days, ten fish per treatment were sacrificed and gene expression of gonadotropin-releasing hormone (m>GnRH-I, GnRH-II, GnRH-IIIm>), gonadotropin subunits-m>¦Âm> (m>FSH-¦Â, LH-¦Âm>), glycoprotein hormone-¦Á (m>GPH-¦Ám>), gonadotropin receptors (m>FSH-R, LH-Rm>), and gonadal aromatase (m>cyp19a1am>) was analyzed. Also, plasma levels of sexual steroids and gonadal reproductive status were studied. Fish exposed to high temperature fluctuations quit spawning, presenting clear signs of gonadal regression. Fish recovered its spawning activity 11 weeks after heat treatment. At endocrine level, m>GnRH-Im> and m>FSH-¦Âm> in both sexes, m>LH-¦Âm> and m>GPH-¦Ám> in males and m>FSH-R, LH-Rm> and m>cyp19a1am> in females decreased significantly in treated fish. Also, a strong reduction in plasma sex steroid levels was found for both sexes. This study demonstrated that pulses of warm water in natural environment during pejerrey spawning season can disrupt all levels of the reproductive axis, impairing reproduction.