Fuss C N, Godwin K O
Aust J Biol Sci. 1975 Jun;28(3):239-49. doi: 10.1071/bi9750239.
The fate of selenium, given as Na2(75)SeO3, or [75Se]selenomethionine, and of [35S]methionine administered intravenously to ewes and lambs, has been examined. The main intention was to follow the incorporation of selenium into protein in a number of tissues, including liver and kidney, and to measure the extent of that incorporation of selenoamino acid, particularly with respect to the administration of selenite. The ewes chosen were lactating ewes with lambs at foot, and the lambs were animals which had been weaned on to fodder low in selenium and were recovering from white muscle disease with selenium therapy. These two experimental situations were chosen as they offered conditions under which selenium incorporation might be considered to be maximal. Entry of isotope into milk was rapid and was greater when 75Se was given as the selenoamino acid than as selenite. In both ewes and lambs greater amounts of activity, derived from selenite, were bound to plasma proteins than to the proteins of milk. This was particularly evident in samples taken some hours after administration. This ability of the plasma to bind selenium was demonstrated by alkaline dialysis. Small, though significant amounts of selenium, derived from Na2(75)SeO3, were incorporated as selenoamino acids into the proteins of liver, kidney and pancreas, as well as into the proteins of milk and plasma. In ewes, both selenomethionine and selenocystine were identified chromatographically in enzyme digests of defatted liver and kidney. Some differences occurred in the distribution of labelled compounds in organs from lactating ewes and recovering lambs. The incorporation of selenium into protein is discussed briefly in relation to the recent findings of an association between selenium and the enzyme glutathione peroxidase.
已对静脉注射给母羊和羔羊的硒酸钠（Na₂(⁷⁵)SeO₃）、[⁷⁵Se]硒代蛋氨酸以及[³⁵S]蛋氨酸的归宿进行了研究。主要目的是追踪硒在包括肝脏和肾脏在内的多种组织中掺入蛋白质的情况，并测定硒代氨基酸的掺入程度，特别是关于亚硒酸盐的给药情况。所选用的母羊是正在哺乳且带有羔羊的母羊，而羔羊是已断奶并食用低硒饲料且正在接受硒疗法治疗白肌病的动物。选择这两种实验情况是因为它们提供了可能认为硒掺入量最大的条件。同位素进入乳汁的速度很快，当以硒代氨基酸形式给予⁷⁵Se时比给予亚硒酸盐时进入乳汁的量更多。在母羊和羔羊中，来自亚硒酸盐的更多活性物质与血浆蛋白结合，而不是与乳汁蛋白结合。这在给药后数小时采集的样本中尤为明显。血浆结合硒的这种能力通过碱性透析得以证明。少量但显著量的来自Na₂(⁷⁵)SeO₃的硒作为硒代氨基酸掺入肝脏、肾脏和胰腺的蛋白质中，以及乳汁和血浆的蛋白质中。在母羊中，在脱脂肝脏和肾脏的酶消化物中通过色谱法鉴定出了硒代蛋氨酸和硒代胱氨酸。在正在哺乳的母羊和正在恢复的羔羊的器官中，标记化合物的分布存在一些差异。结合硒与谷胱甘肽过氧化物酶之间关联的最新研究结果，简要讨论了硒掺入蛋白质的情况。
