Donnerer J, Amann R, Schuligoi R, Lembeck F
Institut für Experimentelle und Klinische Pharmakologie, Universität Graz, Austria.
Naunyn Schmiedebergs Arch Pharmacol. 1990 Sep;342(3):357-61. doi: 10.1007/BF00169449.
This study was performed to examine the metabolism and absorption of intragastrically administered capsaicinoids in the anaesthetized rat. [3H]-dihydrocapsaicin ([3H]-DHC) and unlabelled capsaicin were readily absorbed from the gastrointestinal tract but were almost completely metabolized before reaching the general circulation. A certain degree of biotransformation already took place in the intestinal lumen. Unchanged compounds (identified by chromatography) were present in portal vein blood. There seems to be a saturable absorption and degradation process in the gastrointestinal tract and a very effective metabolism in the liver. Less than 5% of the total amount of extracted radio-activity consisted of unchanged [3H]-DHC in trunk blood and brain 15 min after gastrointestinal application. On the other hand, approximately 50% unchanged [3H]-DHC was detected in these tissues 3 min after i.v. or 90 min after s.c. application of the capsaicinoids. Dihydrocapsaicin (DHC) or [3H]-DHC were metabolized when incubated in vitro with liver tissue but not with brain tissue. The metabolic product(s) did not show capsaicin-like biological activity. It can be concluded that rapid hepatic metabolization limits systemic pharmacological effects of enterally absorbed capsaicin.
本研究旨在检测麻醉大鼠经胃内给予辣椒素类物质后的代谢及吸收情况。[3H] - 二氢辣椒素（[3H] - DHC）和未标记的辣椒素可从胃肠道迅速吸收，但在进入体循环之前几乎完全被代谢。在肠腔内已发生一定程度的生物转化。门静脉血中存在未发生变化的化合物（通过色谱法鉴定）。胃肠道似乎存在一个可饱和的吸收和降解过程，且肝脏中的代谢非常有效。胃肠道给药15分钟后，躯干血液和大脑中提取的放射性总量中，未发生变化的[3H] - DHC占比不到5%。另一方面，静脉注射3分钟后或皮下注射辣椒素类物质90分钟后，在这些组织中检测到约50%未发生变化的[3H] - DHC。二氢辣椒素（DHC）或[3H] - DHC在体外与肝组织孵育时会被代谢，但与脑组织孵育时则不会。代谢产物不具有辣椒素样的生物活性。可以得出结论，肝脏的快速代谢限制了经肠道吸收的辣椒素的全身药理作用。
