萊克多巴胺(Ractopamine)是一種β促效劑(β-agonist)藥物,用以助長豬、牛、火雞生出瘦肉,減少體脂肪。是瘦肉精中最常見的一種,其肉品殘留毒性遠低於具有相同功能的其他動物飼料添加物。
萊克多巴胺原先是研發作為氣喘用藥,但未通過美國食品藥物管理局的人體實驗。
因為發現它能夠增加動物肌肉,因此被使用為飼料添加劑。
證實餵食1 mg/Kg高劑量的萊克多巴胺,將導致心臟肌肉纖維化。
在動物實驗中,小鼠的半數致死量為3547-2545 mg/kg,大鼠的半數致死量為474-365 mg/kg。
在大量食用含有萊克多巴胺殘留的肉類或內臟時,可能引發中毒癥狀,噁心、頭暈、肌肉顫抖、
心悸、血壓上升、促進心血管疾病等。
Previous studies have shown that cattle metabolize ractopamine into four major
glucuronide metabolites (2), which can be deconjugated by β-glucuronidase
先前的研究表明,牛將萊克多巴胺代謝為四種主要的葡醣醛酸苷代謝物(2),
可以通過β-葡醣醛酸苷酶解偶聯。
Glucuronidation is often involved in drug metabolism of substances such as drugs,
pollutants, bilirubin, androgens, estrogens, mineralocorticoids, glucocorticoids,
fatty acid derivatives, retinoids, and bile acids. These linkages involve glycosidic bonds.
葡萄醣醛酸苷化通常涉及諸如藥物,污染物,膽紅素,雄激素,雌激素,鹽皮質激素,糖皮質激素,脂肪酸衍生物,類維生素A和膽汁酸的物質的藥物代謝。這些連接涉及糖苷鍵。
The substances resulting from glucuronidation are known as glucuronides (or glucuronosides)
由葡醣醛酸苷化作用產生的物質被稱為葡醣醛酸苷(或葡醣醛酸苷)
Glucuronidation occurs mainly in the liver, although the enzyme responsible
for its catalysis, UDP-glucuronyltransferase, has been found in all major body organs (e.g., intestine, kidneys, brain, adrenal gland, spleen, and thymus).
葡萄醣醛酸苷化主要發生在肝臟中,儘管負責其催化作用的酶UDP-葡萄醣醛酸基轉移酶
在所有主要的身體器官(例如腸,腎,腦,腎上腺,脾臟和胸腺)中都發現了
From these results, it was concluded that the enzyme described here is a new form
of UDP- glucuronyltransferase isozyme, and its activity showed a peculiar dependence on Mg2+.
從這些結果可以得出結論,此處描述的酶是UDP-葡萄醣醛酸轉移酶同工酶的一種新形式,
其活性顯示出對Mg2+(鎂離子)的特殊依賴性。