The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Instytucka 3 Street, 05-110 Jabłonna, Poland.
Molecules. 2017 Nov 10;22(11):1933. doi: 10.3390/molecules22111933.
The secretion of the hormone melatonin reliably reflects environmental light conditions. Among numerous actions, in seasonal breeders, melatonin may regulate the secretion of the gonadotropins acting via its corresponding receptors occurring in the (). However, it was previously found that the secretory activity of the pituitary may be dependent on the immune status of the animal. Therefore, this study was designed to determine the role of melatonin in the modulation of luteinizing hormone (LH) secretion from the explants collected from saline- and endotoxin-treated ewes in the follicular phase of the oestrous cycle. Twelve Blackhead ewes were sacrificed 3 h after injection with lipopolysaccharide (LPS; 400 ng/kg) or saline, and the were collected. Each was cut into 4 explants, which were then divided into 4 groups: I, incubated with 'pure' medium 199; II, treated with gonadotropin-releasing hormone (GnRH) (100 pg/mL); III, treated with melatonin (10 nmol/mL); and IV, incubated with GnRH and melatonin. Melatonin reduced ( < 0.05) GnRH-induced secretion of LH only in the from saline-treated ewes. Explants collected from LPS-treated ewes were characterized by lower ( < 0.05) GnRH-dependent response in LH release. It was also found that inflammation reduced the gene expression of the GnRH receptor and the MT1 melatonin receptors in the . Therefore, it was shown that inflammation affects the melatonin action on LH secretion from the , which may be one of the mechanisms via which immune/inflammatory challenges disturb reproduction processes in animals.
褪黑素的分泌可靠地反映了环境光照条件。在众多作用中，在季节性繁殖者中，褪黑素可能通过其在 () 中发生的相应受体调节促性腺激素的分泌。然而，先前发现，垂体的分泌活性可能取决于动物的免疫状态。因此，本研究旨在确定褪黑素在调节发情周期卵泡期从盐处理和内毒素处理的母羊采集的 () 中黄体生成素 (LH) 分泌中的作用。在注射脂多糖 (LPS；400ng/kg) 或盐水后 3 小时，处死 12 只黑头羊，并收集。每个 被切成 4 个 ，然后将它们分为 4 组：I，用“纯”199 培养基孵育；II，用促性腺激素释放激素 (GnRH) (100pg/mL) 处理；III，用褪黑素 (10nmol/mL) 处理；IV，用 GnRH 和褪黑素孵育。褪黑素仅在盐水处理的母羊的 GnRH 诱导的 LH 分泌中降低（<0.05）。从 LPS 处理的母羊采集的 表现出较低的 GnRH 依赖性 LH 释放反应（<0.05）。还发现炎症降低了 GnRH 受体和 MT1 褪黑素受体在 中的基因表达。因此，表明炎症影响褪黑素对从 中 LH 分泌的作用，这可能是免疫/炎症挑战扰乱动物生殖过程的机制之一。
