Vieira J G, Nishida S K, Lombardi M T, Abucham J Z, Kasamatsu T S
Departamento de Medicina, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brasil.
Braz J Med Biol Res. 1995 Jun;28(6):633-6.
Glycoprotein hormone free alpha subunit has been used as a marker for some pituitary tumors and to study the reactivity of glycoprotein hormone-producing cells under different circumstances. We describe a highly sensitive and specific immunofluorometric assay for the measurement of serum free alpha subunit levels. The assay is based on a monoclonal antibody, specific for free alpha subunit, bound to microtiter plates. As tracer antibody we employed an europium-labelled free/complexed alpha subunit specific monoclonal antibody. Using overnight incubation and 50-microliters samples, the least detectable dose was of the order of 4 ng/l. Cross-reactivity with LH, TSH, FSH and hCG was 6.5, 1.2, 4.3 and 1.1%, respectively. Normal adult males showed values ranging from 120 to 790 ng/l, not different from normal adult premenopausal females (88 to 604 ng/l). In post-menopausal females, serum concentrations were significantly higher, ranging from 341 to 4071 ng/l. In 56 patients with untreated pituitary tumors (18 "non-secreting", 25 GH-producing and 13 prolactin-producing tumors), 10 showed high values, 3 of them from the first group, 3 from the second and 4 from the third. We conclude that this highly sensitive assay can be a valuable tool for the diagnosis and follow-up of selected patients with pituitary tumors and in other circumstances in which the glycoprotein hormone-producing cells of the pituitary require evaluation.
糖蛋白激素游离α亚基已被用作某些垂体肿瘤的标志物，并用于研究不同情况下产生糖蛋白激素的细胞的反应性。我们描述了一种用于测量血清游离α亚基水平的高度灵敏且特异的免疫荧光测定法。该测定法基于一种与微孔板结合的、对游离α亚基特异的单克隆抗体。作为示踪抗体，我们采用了一种铕标记的游离/复合α亚基特异单克隆抗体。使用过夜孵育和50微升样本，最低可检测剂量约为4 ng/l。与促黄体生成素（LH）、促甲状腺激素（TSH）、促卵泡生成素（FSH）和人绒毛膜促性腺激素（hCG）的交叉反应率分别为6.5%、1.2%、4.3%和1.1%。正常成年男性的值在120至790 ng/l之间，与正常成年绝经前女性（88至604 ng/l）无差异。在绝经后女性中，血清浓度显著更高，范围为341至4071 ng/l。在56例未经治疗的垂体肿瘤患者（18例“无分泌功能”、25例生长激素分泌型和13例催乳素分泌型肿瘤）中，10例显示值升高，其中3例来自第一组，3例来自第二组，4例来自第三组。我们得出结论，这种高度灵敏的测定法对于特定垂体肿瘤患者的诊断和随访以及在其他需要评估垂体产生糖蛋白激素细胞的情况下可能是一种有价值的工具。
