Browning R, Gissendanner S J, Wakefield T
School of Agriculture and Home Economics, Tennessee State University, Nashville 37209-1561, USA.
J Anim Sci. 2000 Mar;78(3):690-8. doi: 10.2527/2000.783690x.
Bovine plasma was assayed to determine whether ergotamine, an ergopeptide isolated from endophytic tall fescue, affected cortisol, triiodothyronine, insulin, and glucagon concentrations. In Exp. 1, four heifers received an i.v. bolus injection of ergotamine tartrate (19 microg/kg BW) or saline vehicle in a simple crossover design 2 d after induced luteolysis. Oxytocin (100 USP units) was i.v. administered 4 h after ergotamine or saline. Treatment x time affected (P < .01) respiration rates and plasma concentrations of cortisol, triiodothyronine, insulin, and glucagon. Respiration rates were elevated (P < .01) 2 to 7 h after ergotamine, but they were unchanged after saline. Plasma cortisol concentrations were increased (P < .01) 1 to 3 h after ergotamine but not after saline. Plasma triiodothyronine was elevated 2 h after ergotamine, but it was unchanged in response to saline. Insulin decreased (P < .01) and glucagon increased (P < .01) during the 1st h after ergotamine, but not in response to saline. A second increase (P < .01) of glucagon was observed 3 h after ergotamine. In Exp. 2, six cows were treated with an i.v. bolus injection of ergotamine (20 microg/kg BW) or saline in a simple crossover design 10 d after receiving a s.c. ear implant containing norgestomet. Oxytocin (100 USP units) was i.v. administered 4 h after ergotamine or saline. Treatment x time affected (P < .001) respiration rates, cortisol, insulin, and glucagon and tended to influence (P = .12) triiodothyronine concentrations. Respiration rates were elevated (P < .01) 1 to 7 h after ergotamine but were unaltered by saline. Plasma cortisol was elevated (P < .01) 1 to 5 h after ergotamine, but not in response to saline. Plasma triiodothyronine was elevated (P < .01) 1 to 2 h after ergotamine, but not after saline. Insulin was decreased (P < .01) and glucagon increased (P < .01) within 1 h after ergotamine treatment, but they were not altered by saline. A second increase (P < .01) of glucagon occurred by 4 h after ergotamine. In Exp. 1 and 2, glucagon increased (P < .01) 1 h after oxytocin in saline and ergotamine cows. Results indicate that ergotamine can alter plasma concentrations of hormones that mediate nutrient metabolism and thermoregulation in cattle.
对牛血浆进行分析，以确定从内生高羊茅中分离出的麦角肽麦角胺是否会影响皮质醇、三碘甲状腺原氨酸、胰岛素和胰高血糖素的浓度。在实验1中，4头小母牛在诱导黄体溶解2天后，采用简单交叉设计，静脉推注酒石酸麦角胺（19微克/千克体重）或生理盐水载体。在注射麦角胺或生理盐水4小时后，静脉注射催产素（100美国药典单位）。处理×时间对呼吸频率以及皮质醇、三碘甲状腺原氨酸、胰岛素和胰高血糖素的血浆浓度有影响（P < 0.01）。注射麦角胺后2至7小时呼吸频率升高（P < 0.01），但注射生理盐水后呼吸频率无变化。注射麦角胺后1至3小时血浆皮质醇浓度升高（P < 0.01），而注射生理盐水后无变化。注射麦角胺后2小时血浆三碘甲状腺原氨酸升高，但注射生理盐水后无变化。注射麦角胺后第1小时胰岛素降低（P < 0.01），胰高血糖素升高（P < 0.01），但注射生理盐水后无此变化。注射麦角胺后3小时观察到胰高血糖素再次升高（P < 0.01）。在实验2中，6头母牛在接受含诺孕美特的皮下耳部植入物10天后，采用简单交叉设计，静脉推注麦角胺（20微克/千克体重）或生理盐水。在注射麦角胺或生理盐水4小时后，静脉注射催产素（100美国药典单位）。处理×时间对呼吸频率、皮质醇、胰岛素和胰高血糖素有影响（P < 0.001），并倾向于影响（P = 0.12）三碘甲状腺原氨酸浓度。注射麦角胺后1至7小时呼吸频率升高（P < 0.01），但注射生理盐水后无变化。注射麦角胺后1至5小时血浆皮质醇升高（P < 0.01），而注射生理盐水后无变化。注射麦角胺后1至2小时血浆三碘甲状腺原氨酸升高（P < 0.01），但注射生理盐水后无变化。麦角胺处理后1小时内胰岛素降低（P < 0.01），胰高血糖素升高（P < 0.01），但注射生理盐水后无此变化。注射麦角胺后4小时胰高血糖素再次升高（P < 0.01）。在实验1和2中，注射生理盐水和麦角胺的母牛在注射催产素后1小时胰高血糖素均升高（P < 0.01）。结果表明，麦角胺可改变介导牛营养代谢和体温调节的激素的血浆浓度。
