Stegelmeier B L, James L F, Panter K E, Molyneux R J
USDA Agriculture Research Service, Poisonous Plant Research Laboratory, Logan, UT 84321, USA.
Vet Hum Toxicol. 1995 Aug;37(4):336-9.
Locoweed intoxication or locoism results when animals continuously graze certain plants of the general Astragalus or Oxytropis. The locoweed toxin, swainsonine, is water soluble and is rapidly absorbed and eliminated. The purpose of this study was to determine the distribution of swainsonine in tissues of sheep eating locoweed and to determine if the tissue swainsonine concentrations change with continued locoweed ingestion. Fifteen cross-breed whethers were divided into 3 groups of 5 each and fed alfalfa pellets (Group 1) or alfalfa pellets with 10% Astragalus lentiginosus for 13 d (Group 2) or for 21 d (Group 3). After the feeding periods, the animals were slaughtered and tissues were collected, frozen and later analyzed for swainsonine using an in vitro, alpha-mannosidase inhibition assay. Significant alpha-mannosidase inhibitory activity (interpreted as ng/ml of swainsonine) was detected in whole blood, skeletal muscle, brain, kidney, liver, thyroid and urine. The swainsonine concentrations in tissues were significantly correlated with daily swainsonine intake (r = 0.58 to 0.96). With the exception of kidney, longer exposure did not result in significant increases in the swainsonine concentrations in blood, muscle, brain, liver or thyroid. Liver had the highest swainsonine concentrations with 3049 +/- 1952 and 3947 +/- 457 ng/ml (mean +/- SD) in Groups 2 and 3 respectively. Swainsonine concentrations varied widely within the groups suggesting individual animal variability in swainsonine absorption, metabolism and excretion. These findings suggest that swainsonine is present in tissues of animals eating locoweed and that in most tissues the amount was directly correlated to the swainsonine dose ingested, but not to the length of exposure.
当动物持续啃食黄芪属或棘豆属的某些植物时，会导致疯草中毒或疯草病。疯草毒素苦马豆素是水溶性的，能迅速被吸收和排泄。本研究的目的是确定苦马豆素在食用疯草的绵羊组织中的分布，并确定随着持续摄入疯草，组织中苦马豆素浓度是否会发生变化。将15只杂交阉羊分为3组，每组5只，分别饲喂苜蓿颗粒（第1组）或添加10%斑点黄芪的苜蓿颗粒，持续13天（第2组）或21天（第3组）。饲喂期结束后，宰杀动物，收集组织，冷冻，随后使用体外α-甘露糖苷酶抑制试验分析苦马豆素。在全血、骨骼肌、脑、肾、肝、甲状腺和尿液中检测到显著的α-甘露糖苷酶抑制活性（解释为苦马豆素的纳克/毫升）。组织中的苦马豆素浓度与每日苦马豆素摄入量显著相关（r = 0.58至0.96）。除肾脏外，较长时间的接触并未导致血液、肌肉、脑、肝或甲状腺中苦马豆素浓度显著增加。肝脏中的苦马豆素浓度最高，第2组和第3组分别为3049±1952和3947±457纳克/毫升（平均值±标准差）。各组内苦马豆素浓度差异很大，表明个体动物在苦马豆素吸收、代谢和排泄方面存在差异。这些发现表明，苦马豆素存在于食用疯草的动物组织中，并且在大多数组织中，其含量与摄入的苦马豆素剂量直接相关，但与接触时间无关。
