Miller D W, Blache D, Boukhliq R, Curlewis J D, Martin G B
Faculty of Agriculture (Animal Science), University of Western Australia, Nedlands, Australia.
J Reprod Fertil. 1998 Mar;112(2):347-56. doi: 10.1530/jrf.0.1120347.
Nutrition influences the reproductive axis via alteration of gonadotrophin secretion. However, a link between nutrition and the secretion of GnRH, which drives the axis, has yet to be established. The aim of the present study was to measure the change in the concentrations of metabolic substances in the cerebrospinal fluid of adult male sheep offered a diet designed to maintain constant gonadotrophin secretion (Group M; n = 6), or a diet known to increase gonadotrophin secretion (Group M + L; n = 6). On days 1, 3 and 10 of the dietary treatments, cerebrospinal fluid and jugular blood were sampled and analysed for metabolic fuels (glucose, amino acids and free fatty acids) and metabolic hormones (insulin, insulin-like growth factor I, GH, prolactin, cortisol and the thyroid hormones). On day 11 of the dietary treatment, LH pulse frequency and mean FSH concentrations in Group M + L had increased relative to Group M and to day 0. Plasma concentrations of prolactin and insulin on days 3 and 10, and glucose and insulin-like growth factor I on day 10, were higher in Group M + L than in Group M, but only cerebrospinal fluid concentrations of insulin, glucose and certain amino acids were affected by the dietary treatments on days 3 and 10. Cerebrospinal fluid, but not plasma, concentrations of aspartate, tyrosine, cystine, phenylalanine and arginine on day 3, and glutamine, gamma-aminobutyric acid, threonine, alanine on days 3 and 10, were higher in Group M + L relative to Group M. On day 10, plasma and cerebrospinal fluid concentrations of arginine, phenylalaine, proline, tyrosine, methionine and phosphoserine, but only the plasma concentrations of linoleic acid, aspartate and serine, were higher in Group M + L than in Group M. Concentrations of triiodothyronine, thyroxine, and cortisol in plasma and cerebrospinal fluid were not affected. These results show that the nutritional stimulation of gonadotrophin secretion is accompanied primarily by fluctuations in plasma and cerebrospinal fluid concentrations of insulin and certain amino acids, which suggests that, when nutritional status is improved, insulin, amino acids and possibly glucose interact to modulate GnRH secretion.
营养通过改变促性腺激素的分泌来影响生殖轴。然而，营养与驱动该轴的促性腺激素释放激素（GnRH）分泌之间的联系尚未确立。本研究的目的是测量成年雄性绵羊脑脊液中代谢物质浓度的变化，这些绵羊分别给予旨在维持促性腺激素分泌恒定的日粮（M组；n = 6），或已知会增加促性腺激素分泌的日粮（M + L组；n = 6）。在日粮处理的第1、3和10天，采集脑脊液和颈静脉血，并分析代谢燃料（葡萄糖、氨基酸和游离脂肪酸）和代谢激素（胰岛素、胰岛素样生长因子I、生长激素、催乳素、皮质醇和甲状腺激素）。在日粮处理的第11天，M + L组的促黄体生成素（LH）脉冲频率和平均促卵泡激素（FSH）浓度相对于M组和第0天有所增加。M + L组在第3天和第10天的血浆催乳素和胰岛素浓度，以及在第10天的葡萄糖和胰岛素样生长因子I浓度均高于M组，但仅在第3天和第10天，日粮处理影响了脑脊液中的胰岛素、葡萄糖和某些氨基酸浓度。相对于M组，M + L组在第3天脑脊液中天门冬氨酸、酪氨酸、胱氨酸、苯丙氨酸和精氨酸的浓度，以及在第3天和第10天脑脊液中谷氨酰胺、γ-氨基丁酸、苏氨酸、丙氨酸的浓度更高。在第10天，M + L组血浆和脑脊液中精氨酸、苯丙氨酸、脯氨酸、酪氨酸、蛋氨酸和磷酸丝氨酸的浓度，但只有血浆中亚油酸、天门冬氨酸和丝氨酸的浓度高于M组。血浆和脑脊液中三碘甲状腺原氨酸、甲状腺素和皮质醇的浓度未受影响。这些结果表明，营养对促性腺激素分泌的刺激主要伴随着血浆和脑脊液中胰岛素和某些氨基酸浓度的波动，这表明当营养状况改善时，胰岛素、氨基酸以及可能还有葡萄糖相互作用来调节GnRH的分泌。
