克伦特罗对绵羊肝脏血流量和氮代谢的影响

在4头门静脉、肝静脉、肠系膜静脉和股动脉上安装血管导管的绵羊中研究了克伦特罗（CL,0.8 mg/kgBW,肠系膜静脉给药,每天2次,连续5 d）对其肝脏生长代谢的影响。结果表明:CL对肝脏血流量影响较小。而在CL作用下绵羊血浆中尿素氮水平明显下降,肝静脉和门静脉血液尿素氮流量分别减少16.86％（P<0.01）和15.51％（P<0.05）。肝静脉多肽流量在CL处理期也较对照期下降38.71％（P<0.01）,门静脉处多肽水平处理期则与对照期相当。克伦特罗还增加绵羊肝脏IGF-I的合成和分泌,门静脉和肝静脉中的增加幅度分别为38.84％（P<0.01）和33.18％（P<0.01）。提示CL可通过增强对绵羊肝脏氮的储留及肝脏IGF-I的合成和分泌从而促进机体的生长代谢。

Effects of Clenbuterol on the Hepatic Blood Flux and Metabolism of Nitrogen in Sheep

Four sheep installed chronic polycatheters in the portal vein,hepatic vein.mesenteric vein and femoral artery were used to study the effects of clenbuterol (0.8 mg/kg BW,twice daily for 5 d) on hepatic metabolism. The results showed that clenbuterol had a little effect on the blood flux of sheep liver. However, there was a decline of the serum urea-nitrogen level distinctly during clenbuterol treatment period, the urea-nitrogen flux of hepatic and portal vein were decreased by 16.86% (P<0.01) and 15.51% (P<0.05),respectively. The pep-tide flux of hepatic vein was also decreased by 38.71% (P<0.01) compared with that of control,but the pep-tide level of portal vein in treatment period was similar to control. Moreover, the IGF-I level of hepatic synthesis and secretion was elevated with clenbuterol treatment, the IGF-I flux of portal vein and hepatic vein were increased by 38.84% (P<0.01) and 33.18% (P < 0.05), respectively. These data suggest that clenbuterol would improve growth metabolism by increasing nitrogen deposition and IGF-I level of liver in sheep.