Seshadri M S, Chan Y L, Wilkinson M R, Mason R S, Posen S
Clin Sci (Lond). 1985 Mar;68(3):311-9. doi: 10.1042/cs0680311.
A renal adenylate cyclase system was assessed for its suitability in the performance of parathyroid hormone (PTH) bioassays. Membrane preparations from 1 week old chicks were found to be more sensitive to PTH than material from humans, dogs or rats. Because of the presence of non-specific inhibitors and stimulators of adenylate cyclase in human serum, each serum sample was assayed in the presence and in the absence of a specific PTH inhibitor and the difference was used to calculate PTH activity. Calcium, an inhibitor of adenylate cyclase, was either removed from serum samples by pretreatment with Chelex resin or chelated during assay by means of EGTA. Human and bovine PTH (1-34) stimulated adenylate cyclase in this system to the same extent. The lower limit of detectability was 19.5 pg/ml (final concentration). The intra-assay coefficient of variation at a final concentration of 45 pg/ml was 18%. The index of precision was 0.08 +/- 0.04 (n = 7). When synthetic human PTH (1-34) was infused into three normal volunteers, the mean biological half-life of this material was found to be 3.2 min. PTH-like bioactivity could be routinely detected in sera from normal rats, while such activity was significantly decreased in rats subjected to thyroparathyroidectomy.
评估了一种肾腺苷酸环化酶系统用于甲状旁腺激素（PTH）生物测定的适用性。发现1周龄雏鸡的膜制剂对PTH比人、狗或大鼠的材料更敏感。由于人血清中存在腺苷酸环化酶的非特异性抑制剂和刺激剂，每个血清样本在有和没有特异性PTH抑制剂的情况下进行测定，并利用两者的差异来计算PTH活性。通过用螯合树脂预处理从血清样本中去除腺苷酸环化酶的抑制剂钙，或在测定过程中通过乙二醇双（2-氨基乙基醚）四乙酸（EGTA）将其螯合。人甲状旁腺激素（1-34）和牛甲状旁腺激素（1-34）在该系统中对腺苷酸环化酶的刺激程度相同。可检测下限为19.5 pg/ml（终浓度）。在终浓度为45 pg/ml时，测定内变异系数为18%。精密度指数为0.08±0.04（n = 7）。当将合成人甲状旁腺激素（1-34）注入三名正常志愿者体内时，发现该物质的平均生物半衰期为3.2分钟。在正常大鼠的血清中可常规检测到PTH样生物活性，而在进行甲状腺甲状旁腺切除术的大鼠中，这种活性显著降低。
