Rokkas T, Vaja S, Taylor P, Murphy G M, Dowling R H
Gastroenterology Unit, UMDS of Guy's Hospital, London, England.
Digestion. 1990;46 Suppl 2:378-82. doi: 10.1159/000200411.
The aim of this study was to examine the relative importance of the enzymes ornithine decarboxylase (ODC) and diamine oxidase (DAO) in intestinal polyamine metabolism in normal rats. To study this we measured jejunal and ileal DAO and ODC activities and polyamine levels 2 h after injecting, in non-fasting male Wistar rats, either normal saline (controls) or a large dose of i.v. heparin to deplete intestinal mucosal DAO stores. We found that heparin significantly reduced mean DAO activity (p less than 0.001). As a result putrescine levels increased significantly in both jejunum (p less than 0.02) and ileum (p less than 0.01). Heparin-induced DAO depletion had no significant effect on spermine and spermidine levels at either site. The increased putrescine was associated with reduced ODC activity in both jejunum (p less than 0.01) and ileum (p less than 0.05). ODC activity correlated negatively with putrescine (p less than 0.001). These results suggest that (i) in normal rats, DAO is more important than ODC in regulating mucosal putrescine levels and (ii) putrescine exerts feedback inhibition of ODC.
本研究的目的是检测鸟氨酸脱羧酶（ODC）和二胺氧化酶（DAO）在正常大鼠肠道多胺代谢中的相对重要性。为了研究这一点，我们在非禁食雄性Wistar大鼠中，注射生理盐水（对照组）或大剂量静脉注射肝素以耗尽肠道黏膜DAO储备后2小时，测量空肠和回肠的DAO和ODC活性以及多胺水平。我们发现肝素显著降低了平均DAO活性（p<0.001）。结果，空肠（p<0.02）和回肠（p<0.01）中的腐胺水平均显著升高。肝素诱导的DAO耗竭对两个部位的精胺和亚精胺水平均无显著影响。空肠（p<0.01）和回肠（p<0.05）中腐胺增加均与ODC活性降低有关。ODC活性与腐胺呈负相关（p<0.001）。这些结果表明：（i）在正常大鼠中，DAO在调节黏膜腐胺水平方面比ODC更重要；（ii）腐胺对ODC发挥反馈抑制作用。
