Yandle T G, Richards A M, Gilbert A, Fisher S, Holmes S, Espiner E A
Department of Endocrinology, Christchurch Hospital, New Zealand.
J Clin Endocrinol Metab. 1993 Apr;76(4):832-8. doi: 10.1210/jcem.76.4.8473392.
A RIA for human brain natriuretic peptide (BNP) was developed. Both BNP and atrial natriuretic peptide (ANP) were extracted from human plasma with Vycor glass powder (71% recovery for BNP). The assay had a minimum detection limit of 0.45 fmol/tube and an IC50 of 9 fmol/tube. The within-assay coefficients of variation were 11.4% at 4 pmol/L and 3.2% at 22 pmol/L, and the between-assay coefficient of variation was 11% at 24 pmol/L. There was no significant loss of immunoreactive (IR)-BNP in plasma samples stored at -80 C for 4 weeks. Low rates of labeled BNP and IR-BNP degradation occurred in EDTA plasma incubated at 37 C. The mean venous plasma IR-BNP (6.3 +/- 0.3 pmol/L) in normal subjects (n = 48) was significantly lower than plasma ANP (8.4 +/- 0.6 pmol/L). In contrast to ANP, IR-BNP did not increase when normotensive or hypertensive subjects changed from erect to supine posture. Markedly elevated levels were found in patients with congestive heart failure (mean IR-BNP, 87 +/- 11 pmol/L; ANP, 87 +/- 12 pmol/L; n = 35), recent myocardial infarction (mean IR-BNP, 60 +/- 9 pmol/L; ANP, 33 +/- 6 pmol/L; n = 7), and chronic renal failure. High pressure liquid chromatography of plasma extracts from heart failure subjects revealed both high (mol wt, 10,000) and low (mol wt, 4,000) mol wt IR-BNP. High mol wt BNP was the major component (mean ratio, 1.9:1) and was linearly correlated with low mol wt BNP (r = 0.99). HPLC of plasma extracts from three normal subjects receiving constant infusions of human BNP (2 pmol/kg.min) showed a single major peak eluting in the position of hBNP-32, with no evidence of high mol wt material. These results show that whereas marked elevations in BNP occur in circulatory disorders, a major (> 50%) and consistent contribution to immunoreactivity is due to precursor forms. Further, compared to ANP, there is no IR-BNP response to supine posture in normal and hypertensive subjects.
开发了一种用于检测人脑钠肽（BNP）的放射免疫分析方法。BNP和心房钠尿肽（ANP）均用人造玻璃粉从人血浆中提取（BNP的回收率为71%）。该分析方法的最低检测限为0.45 fmol/管，半数抑制浓度（IC50）为9 fmol/管。批内变异系数在4 pmol/L时为11.4%，在22 pmol/L时为3.2%，批间变异系数在24 pmol/L时为11%。储存在-80℃达4周的血浆样本中，免疫反应性（IR）-BNP无明显损失。在37℃孵育的乙二胺四乙酸（EDTA）血浆中，标记的BNP和IR-BNP降解率较低。正常受试者（n = 48）的平均静脉血浆IR-BNP（6.3±0.3 pmol/L）显著低于血浆ANP（8.4±0.6 pmol/L）。与ANP不同，血压正常或高血压的受试者从直立位变为仰卧位时，IR-BNP并未升高。充血性心力衰竭患者（平均IR-BNP，87±11 pmol/L；ANP，87±12 pmol/L；n = 35）、近期心肌梗死患者（平均IR-BNP，60±9 pmol/L；ANP，33±6 pmol/L；n = 7）和慢性肾衰竭患者的BNP水平明显升高。对心力衰竭患者血浆提取物进行高压液相色谱分析，发现存在高分子量（分子量10,000）和低分子量（分子量4,000）的IR-BNP。高分子量BNP是主要成分（平均比例为1.9:1），且与低分子量BNP呈线性相关（r = 0.99）。对三名持续输注人BNP（2 pmol/kg·min）的正常受试者的血浆提取物进行HPLC分析，显示在hBNP-32的位置有一个单一的主峰洗脱，没有高分子量物质的迹象。这些结果表明，虽然在循环系统疾病中BNP水平显著升高，但免疫反应性的主要（>50%）且一致的贡献来自前体形式。此外，与ANP相比，正常和高血压受试者的IR-BNP对仰卧位无反应。
