Metabolic responses of lactating dairy cows to single and multiple subcutaneous injections of glucagon
Metabolic responses of lactating dairy cows to single and multiple subcutaneous injections of glucagon
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DOI：
10.3168/jds.s0022-0302(03)73796-5
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发表时间：
2003-06-01
影响因子：
3.5
通讯作者：
Beitz, DC
中科院分区：
文献类型：
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作者：
Bobe, G;Sonon, RN;Beitz, DC
持续静脉输注胰高血糖素可改善泌乳奶牛的碳水化合物状况，而不会增加血浆NEFA浓度。目的是测试是否单次皮下注射和多次皮下注射胰高血糖素在14天内以8小时的间隔递送，改善泌乳奶牛的碳水化合物状态，而不增加血浆BHBA和NEFA的浓度。在单次注射实验中，4头泌乳中期奶牛分别注射2.5和5 mg胰高血糖素，间隔1周。在多次注射实验中，从产后第8天开始，将9头奶牛随机分配至3个治疗组，每8 h皮下注射0、2.5或5 mg胰高血糖素，持续14 d。单次皮下注射胰高血糖素可增加血浆胰高血糖素浓度，单次和多次皮下注射胰高血糖素可增加血浆葡萄糖浓度，5 mg剂量时增加幅度较大。在两个实验中，注射5 mg胰高血糖素增加血浆胰岛素浓度，而2.5 mg剂量仅在多次注射实验中增加血浆胰岛素。葡萄糖和胰岛素对注射5 mg胰高血糖素的反应在整个14天的注射期内持续存在。单次注射实验中血浆NEFA浓度降低，多次注射实验中注射5 mg胰高血糖素后BHBA浓度降低。这些结果证明，在14天内单次和多次注射5 mg胰高血糖素可持续改善奶牛的碳水化合物状态，并降低血浆NEFA和BHBA的浓度。
Continuous, intravenous infusions of glucagon improve carbohydrate status in lactating dairy cows without increasing concentrations of plasma NEFA. The objective was to test whether single subcutaneous injections and multiple subcutaneous injections of glucagon delivered at 8-h intervals over 14 d improve the carbohydrate status in lactating dairy cows without increasing concentrations of plasma BHBA and NEFA. In a single-injection experiment, four midlactation cows each were injected with 2.5 and 5 mg of glucagon 1 wk apart. In a multiple-injection experiment, nine cows, assigned randomly to three treatments, were injected subcutaneously with 0, 2.5, or 5 mg of glucagon every 8 h for 14 d, beginning at d 8 postpartum. Single subcutaneous injections of glucagon increased concentrations of plasma glucagon and single and multiple subcutaneous injections of glucagon increased concentrations of plasma glucose, with larger increases at the 5-mg dosage. Injections of 5 mg of glucagon increased concentrations of plasma insulin in both experiments, whereas the 2.5-mg dosage increased plasma insulin only in the multiple-injection experiment. The response of glucose and insulin to injections of 5 mg of glucagon persisted throughout the 14-d injection period. Concentrations of plasma NEFA decreased in the single-injection experiment, and concentrations of BHBA decreased after 5 mg of glucagon was injected in the multiple-injection experiment. These results document that both single and multiple injections of 5 mg of glucagon over 14 d consistently improve the carbohydrate status of dairy cows and decrease concentrations of plasma NEFA and BHBA.