Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK; Department of Immunology, Centre for Neuroendocrinology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa.
Department of Immunology, Centre for Neuroendocrinology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa.
Gen Comp Endocrinol. 2022 Dec 1;329:114127. doi: 10.1016/j.ygcen.2022.114127. Epub 2022 Sep 20.
Understanding the hypothalamic factors regulating reproduction facilitates maximising the reproductive success of breeding programmes and in the management and conservation of threatened species, including African lions. To provide insight into the physiology and pathophysiology of the hypothalamic-pituitary-gonadal reproductive axis in lions, we studied the luteinising hormone (LH) and steroid hormone responses to gonadotropin-releasing hormone (GnRH) and its upstream regulator, kisspeptin. Six young (13.3 ± 1.7 months, 56.2 ± 4.3 kg) and four adult (40.2 ± 1.4 months, 174 ± 6 kg) male lions (Ukutula Conservation Centre, South Africa) were used in this study. Lions were immobilised with a combination of medetomidine and ketamine and an intravenous catheter was placed in a jugular, cephalic or medial saphenous vein for blood sampling at 10-min intervals for 220 min. The ten-amino acid kisspeptin which has full intrinsic activity (KP-10, 1 µg/kg) and GnRH (1 µg/kg) were administered intravenously to study their effects on LH and steroid hormone plasma concentrations, measured subsequently by ELISA and liquid chromatography tandem mass spectrometry (LC-MS/MS), respectively. Basal LH levels were similarly low between the age groups, but testosterone and its precursor levels were higher in the adult animals. Adult lions showed a significant LH response to KP-10 (10-fold) and GnRH (11-fold) administration (p < 0.05 and P < 0.001, respectively) whereas in young lions LH increased significantly only in response to GnRH. In adults alone, testosterone and its precursors steadily increased in response to KP-10, with no significant further increase in response to GnRH. Plasma levels of glucocorticoids in response to KP-10 remained unchanged. We suggest that provocative testing of LH and steroid stimulation with kisspeptin provides a new and sensitive tool for determining reproductive status and possibly an index of exposure to stress, environmental insults such as disease, endocrine disruptors and nutritional status. 272 words.
了解调节繁殖的下丘脑因素有助于最大限度地提高繁殖计划的繁殖成功率，并有助于管理和保护濒危物种，包括非洲狮。为了深入了解狮子下丘脑-垂体-性腺生殖轴的生理学和病理生理学，我们研究了促性腺激素释放激素（GnRH）及其上游调节剂 kisspeptin 对黄体生成素（LH）和类固醇激素的反应。本研究使用了 6 只幼狮（13.3 ± 1.7 个月，56.2 ± 4.3 kg）和 4 只成年雄狮（174 ± 6 kg）（南非 Ukutula 保护中心）。狮子被用甲磺酸右美托咪定和氯胺酮混合麻醉，并在颈静脉、头静脉或内侧隐静脉中放置静脉导管，以便在 220 分钟内每隔 10 分钟采集一次血样。我们用具有完整内在活性的 10 个氨基酸 kisspeptin（KP-10，1 µg/kg）和 GnRH（1 µg/kg）进行静脉内给药，以研究它们对 LH 和类固醇激素血浆浓度的影响，随后分别通过 ELISA 和液相色谱串联质谱法（LC-MS/MS）进行测量。两个年龄组的基础 LH 水平相似较低，但成年动物的睾酮及其前体水平较高。成年狮子对 KP-10（10 倍）和 GnRH（11 倍）给药均显示出显著的 LH 反应（p < 0.05 和 P < 0.001），而幼狮仅对 GnRH 给药后 LH 显著增加。仅在成年动物中，KP-10 引起睾酮及其前体水平持续增加，而对 GnRH 无明显进一步增加。KP-10 引起的糖皮质激素的血浆水平保持不变。我们认为，LH 和类固醇刺激的促性腺激素刺激测试提供了一种新的、敏感的工具，可用于确定生殖状态，并且可能是对压力、环境应激（如疾病、内分泌干扰物和营养状况）暴露的指标。272 个单词。
