环-磷酸鸟苷（cGMP）是近几年来在生物医学中极受注意的重要活性物质之一。它和环-磷酸腺苷（cAMP）一起，对细胞的生长、繁殖及生理活动起着重要的调节作用。根据文献报导及我们自己和兄弟单位协作研究的初步结果，它们和中医“虚证”及一些重要疾病如急性心肌梗塞、慢性肾炎等都有重要关系。但cGMP在体内含量甚低，测定较难。本文报导抗原制备，诱导生成抗体的实验结果以及对抗体的鉴定、样品处理方法的改进、放射免疫方法的建立及对方法所作的考核结果。

A modified method of cGMP RIA is presented in this paper. Succinylation of cGMP was catalyzed by triethylamine in an aqueous medium and the 2'-o-ScGMP thus formed was conjugated with BSA or thyroglobulin under the action of EDCI. The ScGMP-BSA or ScGMP-TG obtained was used as an antigen to induce antibody in rabbits.

3

H-cGMP (15 Ci/mmol) was used as the labelled ligand. Both labelled and unlabelled cGMP were acetylated with acetic anhydride and triethylamine prior to the addition of antiserum. K

a

was estimated to be 2×10

9

M

-1

; the final dilution of antiserum was 1:3000; the sensitivity of the calibration curve was 0.03 pmol; and the cross reaction with cAMP was 1:500. Treatment of plasma samples was improved by adding 1/10 volume of 3.3% acetic acid in ethanol and heating at 70℃ for 4 minutes to precipitate proteins. 100µl of the supernatant was used directly in each tube for immunoassay reaction. The procedure was thus simplified

since there involved almost no dilution of plasma. The within-assay variance and between-assay variance were 8.0% and 7.2% respectively. The cGMP content of normal plasma was found to be 4.75±0.32 pmol/ml (n=21)

which was very close to the values reported in recent literatures.