Burhol P G, Lygren I, Waldum H L
Scand J Gastroenterol. 1978;13(7):807-13. doi: 10.3109/00365527809182195.
A sensitive, precise, and specific radioimmunoassay for vasoactive intestinal polypeptide (VIP) is described, with a detection limit of 0.8 pmol/l, within assay precision of 7.8%, and between assay precision of 13.1%. The final dilution of the antiserum to bind 50% of 0.9 fmol 125I-labeled VIP was 1:250000. The antiserum showed an effective equilibrium constant (Keff) according to Scatchard of 7.4 x 1011 l/mol, an average equilibrium constant (Ko) according to Sips of 7.3 x 1011 l/mol, an index of heterogeneity (alpha) according to Sips of 0.99, and a negligible cross-reactivity with secretin. 125I-labeled VIP was prepared by a modified Chloramine-T method, and the label purified on a Sephadex G-15 column followed by a SP Sephadex C-25 column had a specific radioactivity of 1700 muCi/nmol. The present assay allows measurements of fasting plasma VIP in the very low pmol/l range and the increase and gradual fall in plasma VIP subsequent to a brief period of duodenal acidification.
本文描述了一种用于血管活性肠肽（VIP）的灵敏、精确且特异的放射免疫测定法，其检测限为0.8 pmol/l，批内精密度为7.8%，批间精密度为13.1%。结合50%的0.9 fmol 125I标记VIP的抗血清最终稀释度为1:250000。根据Scatchard法，该抗血清的有效平衡常数（Keff）为7.4×1011 l/mol，根据Sips法的平均平衡常数（Ko）为7.3×1011 l/mol，根据Sips法的异质性指数（α）为0.99，与促胰液素的交叉反应可忽略不计。125I标记的VIP通过改良的氯胺-T法制备，在Sephadex G-15柱上纯化后再经SP Sephadex C-25柱纯化，其比放射性为1700 μCi/nmol。本测定法能够测量极低pmol/l范围内的空腹血浆VIP，以及十二指肠短暂酸化后血浆VIP的升高和逐渐下降情况。
