Popwell J M, Estienne M J, Kraeling R R, Barb C R, Whitley N C, Utley R V, Rampacek G B
Department of Animal and Dairy Science, University of Georgia, Athens 30602, USA.
J Anim Sci. 1996 May;74(5):1067-73. doi: 10.2527/1996.7451067x.
The relationship of excitatory amino acid (EAA) activity to LH secretion was investigated in ovariectomized crossbred prepuberal gilts (93 +/- 1 kg BW) and Yorkshire barrows (94 +/- 2 kg BW) in two experiments. In Exp. 1, eight gilts received, i.m., saline (S) or 20 mg of Ketamine (K)/kg BW, a noncompetitive EAA receptor antagonist. Within these groups, four then received 10 mg of N-methyl-DL-aspartate (NMA)/kg BW, an EAA agonist, or S i.v. Mean serum LH concentrations were similar among groups before treatment, did not change after S+S, but decreased (P < .05) by 1 h after S+NMA, 3 h after K+S, and 2 h after K+NMA. Serum cortisol concentrations did not change after S+S, but were increased (P < .05) from 30 to 90 min after S+NMA, at 120 min after K+S, and from 30 to 120 min after K+NMA. In Exp. 2, barrows received 2.5 mg of NMA/kg BW i.v. immediately after i.m. injection of S (n = 7) or 19.9 mg of K/kg BW (n = 8). Mean serum LH concentrations for the 2 h before treatment were similar among barrows, but decreased (P < .05) by 2 h after K+NMA and was not altered after S+NMA. Serum cortisol concentrations were increased at 30 min after S+NMA and from 60 to 90 min after K+NMA. We suggest that EAA both inhibit and stimulate LH secretion, with the inhibitory effects lying within the basal hypothalamus and the stimulatory effects lying within higher brain centers.
在两项实验中，研究了去卵巢的杂种初情期前小母猪（体重93±1千克）和约克夏公猪（体重94±2千克）中兴奋性氨基酸（EAA）活性与促黄体生成素（LH）分泌之间的关系。在实验1中，八头小母猪肌肉注射生理盐水（S）或20毫克/千克体重的氯胺酮（K），后者是一种非竞争性EAA受体拮抗剂。在这些组中，四头随后静脉注射10毫克/千克体重的N-甲基-DL-天冬氨酸（NMA），一种EAA激动剂，或生理盐水。治疗前各组平均血清LH浓度相似，S+S后无变化，但S+NMA后1小时、K+S后3小时和K+NMA后2小时降低（P<.05）。S+S后血清皮质醇浓度无变化，但S+NMA后30至90分钟、K+S后120分钟以及K+NMA后30至120分钟升高（P<.05）。在实验2中，公猪在肌肉注射生理盐水（n=7）或19.9毫克/千克体重的K（n=8）后立即静脉注射2.5毫克/千克体重的NMA。治疗前2小时公猪的平均血清LH浓度相似，但K+NMA后2小时降低（P<.05），S+NMA后无变化。S+NMA后30分钟以及K+NMA后60至90分钟血清皮质醇浓度升高。我们认为，EAA既抑制又刺激LH分泌，抑制作用位于下丘脑基部，刺激作用位于更高的脑中枢。
