McLeod K R, Harmon D L, Schillo K K, Mitchell G E
Department of Animal Sciences, University of Kentucky, Lexington 40546-0215.
J Anim Sci. 1995 Jan;73(1):77-87. doi: 10.2527/1995.73177x.
Eight crossbred wethers (51 +/- 2 kg BW), surgically fitted with abomasal cannulas, were used to determine the extent and time course of cysteamine (CSH)-induced depletion of somatostatin (SRIF) in abomasal tissue and associated changes in plasma metabolites, insulin, and growth hormone (GH). Cysteamine was administered as a single i.v. bolus (50 mg.kg BW-1 x 10 min-1) on d 0. Abomasal biopsies were obtained on d -7, -3, 0, 1, 3, and 10. On d 0, additional biopsies were taken at 2, 4, and 8 h after CSH administration. Jugular blood samples were collected over 8 h at 15-min intervals on d -2, 0, and 1. Cysteamine administration decreased (P < .05) tissue SRIF on d 0 (2, 4, and 8 h), 1, and 3; maximal depletion (42 to 55% of Pre-treatment; Pre-trt) occurred during the initial 24 h, returning to Pre-trt by d 10. Gel chromatography of pooled -7 d abomasal tissue extracts showed five peaks of SRIF immunoreactivity; the predominate peak eluted in the same position as synthetic SRIF-14. Plasma glucose, lactate, and NEFA concentrations increased (P = .001) after CSH administration and reached peak at 2 h after treatment and declined to Pre-trt concentrations by 24 h. Insulin increased (P = .001) to a maximum at h 4 and returned to Pre-trt by 24 h. Mean and baseline GH were higher (P < .07) on day of CSH administration, and pulse amplitude was lower (P < .10) on d 0 and 1. These data show that CSH rapidly reduces SRIF in abomasal tissue in a reversible manner; suggesting that CSH-treated sheep may provide a SRIF-deficient model for studying the physiological role of SRIF in ruminants.
选用8只杂种阉羊（体重51±2千克），通过手术安装皱胃套管，以确定半胱胺（CSH）诱导的皱胃组织中生长抑素（SRIF）耗竭的程度和时间进程，以及血浆代谢物、胰岛素和生长激素（GH）的相关变化。在第0天，将半胱胺作为单次静脉推注（50毫克·千克体重-1×10分钟-1）给药。在第-7、-3、0、1、3和10天采集皱胃活检样本。在第0天，在给予CSH后2、4和8小时采集额外的活检样本。在第-2、0和1天，每隔15分钟采集8小时的颈静脉血样。给予半胱胺后，第0天（2、4和8小时）、第1天和第3天的组织SRIF降低（P<0.05）；最大耗竭（预处理前的42%至55%；预处理前）发生在最初24小时内，到第10天恢复到预处理前水平。对第-7天皱胃组织提取物进行凝胶色谱分析，显示出五个SRIF免疫反应峰；主要峰与合成SRIF-14在相同位置洗脱。给予CSH后，血浆葡萄糖、乳酸和非酯化脂肪酸浓度升高（P = 0.001），在治疗后2小时达到峰值，并在24小时内降至预处理前浓度。胰岛素在第4小时升高至最大值（P = 0.001），并在24小时内恢复到预处理前水平。在给予CSH当天，平均GH和基础GH较高（P<0.07），在第0天和第1天脉冲幅度较低（P<0.10）。这些数据表明，CSH以可逆方式迅速降低皱胃组织中的SRIF；表明经CSH处理的绵羊可能为研究SRIF在反刍动物中的生理作用提供一个SRIF缺乏模型。
