Effects of exogenous glucagon on lipids in lipoproteins and liver of lactating dairy cows
Effects of exogenous glucagon on lipids in lipoproteins and liver of lactating dairy cows
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DOI：
10.3168/jds.s0022-0302(03)73886-7
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发表时间：
2003-09-01
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;Ametaj, BN;Beitz, DC
血浆和肝脏中磷脂、游离胆固醇和胆固醇酯浓度降低与脂肪肝有关，脂肪肝是奶牛泌乳早期的一种主要代谢性疾病。目的是测试每日皮下注射7.5和15毫克胰高血糖素是否会影响血浆脂蛋白成分和除三酰甘油以外的肝脏脂质的浓度，胰高血糖素可以降低肝脏三酰甘油的浓度。根据产后第8天肝脏甘油三酯浓度，将32头产荷斯坦奶牛分为“正常”奶牛（n = 8头，甘油三酯含量为肝脏湿量1%）。将敏感奶牛随机分为三组，从产后第8天开始，每8小时皮下注射0毫克（正常奶牛相同）、2.5毫克或5毫克胰高血糖素，持续14天。与生理盐水注射相比，皮下注射胰高血糖素增加或倾向于增加肝脏中磷脂和游离胆固醇的浓度，后者在环境温度低于35度时增加更大。注射胰高血糖素降低或倾向于降低血浆中极低密度脂蛋白（三酰甘油）、高密度脂蛋白(1)-磷脂和高密度脂蛋白(2)游离胆固醇的浓度，后两者在环境温度低于35度时没有变化。结果表明，皮下注射胰高血糖素对泌乳早期奶牛血浆脂质转运的影响很小，而在35℃以下的环境温度下，胰高血糖素对泌乳早期奶牛血浆脂质转运的影响更大，最重要的是，没有迹象表明胰高血糖素有负面影响。
Decreased concentrations of phospholipids, free cholesterol, and cholesteryl ester in plasma and liver are associated with fatty liver, a major metabolic disease of dairy cows in early lactation. The objective was to test whether daily subcutaneous injections of 7.5 and 15 mg of glucagon, which can decrease concentrations of liver triacylglycerol, affect concentrations of plasma lipoprotein components and liver lipids other than triacylglycerol. Multiparous Holstein cows (n = 32) were grouped on the basis of liver triacylglycerol concentrations at d 8 postpartum into "normal" (n = 8; triacylglycerol 1% liver wet wt) cows. Susceptible cows were assigned randomly to three groups and beginning at d 8 postpartum received 0 (same for Normal cows), 2.5, or 5 mg of glucagon by subcutaneous injections every 8 h for 14 d. In comparison to saline injections, subcutaneous injections of glucagon either increased or tended to increase concentrations of phospholipids and free cholesterol in liver, with greater increases of the latter during ambient temperatures below 35degreesC. Glucagon injections decreased or tended to decrease concentrations of very low-density lipoprotein-triacylglycerol, high-density lipoprotein(1)-phospholipids, and high-density lipoprotein(2)-free cholesterol in plasma, with no changes of the latter two during ambient temperatures below 35degreesC. The results indicate that subcutaneously administered glucagon has only minor effects on the lipid transport in plasma of dairy cows in early lactation with more beneficial effects occurring during ambient temperatures below 35degreesC and, most importantly, no indications that glucagon has negative effects.