- 作者: 黃文盛; 阮正雄; 郭熙文; 顏兆雄; 羅家森; 陳維廉
- 作者服務機構: 三軍總醫院核子醫學部甲狀腺實驗室; 台北市立婦幼醫院解剖病理科﹑婦產科; 三軍總醫院內科部甲狀腺實驗室; 三軍總醫院婦產部; 台北中山醫院婦產部
- 中文摘要: 硫酸化作用是胎兒甲狀腺激素代謝的主要替代性徑路,其中母體血中硫酸化3,3'-d1iodothyronine (T2S)濃度被認為與胎兒甲狀腺代謝變化有關,為了進一步探討它對胎兒甲狀腺異常的評估並考慮其未來可用性,我們試圖建立此一放射免疫分析,並對20位無孕婦女,165位不同妊娠期婦女,18位產婦及16組臍血進行比較分析。同時;我們也觀察一位接受甲狀腺激素羊水注射孕婦,在治療前、後血中T2S的變化。此一放射免疫分析最低有效測定閥在5pg,標準曲線在5-200pg區問呈直線分佈,其間每一標準值間均具明顯統計差異(p<0.01),以高低值樣品作連續稀釋獲得之反應曲線與標準曲線比較亦呈平行相關性。此一分析之平均組內及組間變異性係數則分別為7%及15%。 檢體測定結果顯示孕婦血中T2S濃度隨懷孕時間增加而增加,其值在無孕婦女為8ng/dL而在一、二及三期妊娠值分別為30,42及98 ng/dL,各組間呈有意義差別(P<0.01)。臨盆時達到高峰(114ng/dL),並於產後10天降至10ng/dL而臍血濃度則為165ng/dL。孕婦在33週接受羊水注射甲狀腺素(200 ug/週×2)前後T2S值由47ng/dL驟昇至96ng/dL;其他甲狀腺功能檢查則無明顯變化。另4位孕婦在妊婦第三期接受追綜性檢測,其值亦呈一致性上升現象。利用目前建立之T2S放射免疫分析檢測孕婦及新生兒血中濃度變化與國外文獻報告頗為一致,但測定值較低,可能與實驗室間反應物製備過程及分析方式差異有關,因此;建立個別檢測標準及內部標本品管乃屬必要。妊娠末期及羊水注射甲狀腺素後孕婦血中T2S濃度增加,則進一步顯示T2S可能經由胎盤進入母體循環。此一增加是否與胎兒甲狀腺成熟有關以及其在胎兒—胎盤—孕婦間的作用機轉則仍需進一步探討。
- 英文摘要: Sulfation of iodothyronines is a major alternate pathway of thyroid hormone metabolism during fetaldevelopment. Sulfated 3,3'-d1iodothyronine (T2S) is a low end metabolite of this pathway. Its clinicalimplications in the prenatal evaluation of fetal thyroid disorders are now being intensively investigated.A highly sensitive and reproducible radioimmunoassay (RIA) for T2S has been established in our laboratory.The detection threshold of the RIA approximated 5 pg T2S. The dose-response curve of T2S was essentiallylinear between 5-200 pg. An essentially parallel correlation of the dose-response curves for inhibition ofbinding of radiolabeled T2S and T2S antiserum was found between serial dilutions of serum extracts andthe standards. The average intra- and inter-assay coefficients of variation were 7% and 15%, respectively. By applying the T2S RIA, we found that serum titers of T2S in pregnant women increased propor-tionately to the gestational age (first trimester vs. second trimester vs. third trimester: 30.1 ± 1.4 vs. 41.6 ±1.9 vs. 98.0 ± 3.9 ng/dL; p < 0.001 each). A high concentration of T2S was detected in cord and maternalserum at birth as compared to the results for non-pregnant women (165.1 ± 10.3 vs. 113.7 ± 5.6 vs.7.5 ± 0.9 ng/dL). The T2S levels decreased remarkably in maternal circulation 10 days after partuition.Four pregnant women who had two blood samplings four or more weeks apart during the third trimestershowed invariable increases of serum T2S titers at later sampling times. Additionally, in the case of apregnant woman who received two doses of T4 injections (200 g/wk) intraamniotically for a previousCretin birth, the maternal serum levels of T2S increased promptly from 47 mg/dL to 96 ng/dL. Our findings imply that the established T2S RIA is clinically applicable, provide further evidence thatthe coincident increase of serum T2S titers in pregnant women may reflect ontogenesis of fetal thyroid hor-mone maturation, and provide a clue to the fetal thyroid status in the prenatal stage. However, moreknowledge is still needed regarding the transfer and transformation of sulfated iodothyronine(s) from thefetal compartment to maternal circulation.
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