Departamento de Bioquímica, Facultad de Veterinaria, Instituto Universitario de Investigation en Ciencias Ambientales de Aragón, Universidad de Zaragoza, Spain.
Reprod Biol Endocrinol. 2010 Jun 11;8:59. doi: 10.1186/1477-7827-8-59.
Some breeds of sheep are highly seasonal in terms of reproductive capability, and these changes are regulated by photoperiod and melatonin secretion. These changes affect the reproductive performance of rams, impairing semen quality and modifying hormonal profiles. Also, the antioxidant defence systems seem to be modulated by melatonin secretion, and shows seasonal variations. The aim of this study was to investigate the presence of melatonin and testosterone in ram seminal plasma and their variations between the breeding and non-breeding seasons. In addition, we analyzed the possible correlations between these hormones and the antioxidant enzyme defence system activity.
Seminal plasma from nine Rasa Aragonesa rams were collected for one year, and their levels of melatonin, testosterone, superoxide dismutase (SOD), glutathione reductase (GRD), glutathione peroxidase (GPX) and catalase (CAT) were measured.
All samples presented measurable quantities of hormones and antioxidant enzymes. Both hormones showed monthly variations, with a decrease after the winter solstice and a rise after the summer solstice that reached the maximum levels in October-November, and a marked seasonal variation (P < 0.01) with higher levels in the breeding season. The yearly pattern of GRD and catalase was close to that of melatonin, and GRD showed a significant seasonal variation (P < 0.01) with a higher activity during the breeding season. Linear regression analysis between the studied hormones and antioxidant enzymes showed a significant correlation between melatonin and testosterone, GRD, SOD and catalase.
These results show the presence of melatonin and testosterone in ram seminal plasma, and that both hormones have seasonal variations, and support the idea that seasonal variations of fertility in the ram involve interplay between melatonin and the antioxidant defence system.
一些绵羊品种的繁殖能力具有明显的季节性，这种变化受光周期和褪黑素分泌的调节。这些变化会影响公羊的繁殖性能，降低精液质量并改变激素谱。此外，抗氧化防御系统似乎也受到褪黑素分泌的调节，并且存在季节性变化。本研究旨在研究公羊精液中褪黑素和睾酮的存在及其在繁殖季节和非繁殖季节之间的变化。此外，我们还分析了这些激素与抗氧化酶防御系统活性之间的可能相关性。
收集 9 只 Rasa Aragonesa 公羊的精液样本，进行为期一年的研究，并测量其褪黑素、睾酮、超氧化物歧化酶（SOD）、谷胱甘肽还原酶（GRD）、谷胱甘肽过氧化物酶（GPX）和过氧化氢酶（CAT）的水平。
所有样本均检测到可测量数量的激素和抗氧化酶。两种激素均呈现月度变化，冬至后下降，夏至后上升，10 月至 11 月达到最高水平，具有明显的季节性变化（P < 0.01），繁殖季节水平较高。GRD 和过氧化氢酶的年模式与褪黑素相似，GRD 表现出明显的季节性变化（P < 0.01），繁殖季节活性较高。对研究的激素和抗氧化酶进行线性回归分析表明，褪黑素与睾酮、GRD、SOD 和过氧化氢酶之间存在显著相关性。
这些结果表明，公羊精液中存在褪黑素和睾酮，并且这两种激素均具有季节性变化，支持了这样一种观点，即公羊的季节性繁殖能力变化涉及褪黑素和抗氧化防御系统之间的相互作用。
