[Studies for a sensitive radioimmunoassay of beta1-Sp1-glycoprotein (SP1) (author's transl)].

In order to measure beta1-SP1-glycoprotein (SP1), on RIA system by the 2-antibody method was established as a measuring method of the low concentration range. SP1 concentrations were measured by this method in the sera of women in early pregnancy, in the amniotic fluids of late pregnancy, in the sera of malignant tumour patients. Furthermore, SP1 concentrations in the sera of women in early pregnancy as well as E2, E3, progesterone and HCG concentrations in the same samples were measured, and correlations between them were examined. 1) The minimum sensitivity of this measuring system was 3ng/ml. The optimum concentration of samples was between 10 approximately 660ng/ml. 2) The correlation between the data obtained by this RIA method and the SRID method was as close as r = 0.9287. 3) SP1 concentrations in the sera of women in early pregnancy were 0.17 +/- 0.12 microgram/ml in the fifth week of pregnancy, showing an almost straight increase during the course of pregnancy, and were 31.62 +/- 3.20 microgram/ml in the 13th week of pregnancy. 4) SP1 concentrations in amniotic fluids were 1.09 approximately 2.20 microgram/ml and were equal to about 1% of SP1 concentrations in the sera of women in late pregnancy. SP1 concentrations in the sera of umbilical cord blood were 0.13 approximately microgram/ml, which were equal to about 0.1% of SP1 concentrations in the sera of women in late pregnancy. 5) SP1 was detected in all four samples of the choriocarcinoma patients' sera, and the concentrations were 25 approximately 2,600ng/ml. Sp1 was detected in 6 of the 15 samples of the cervical carcinoma patients' sera, and the detection rate was 40%. SP1 was detected in 3 of the 6 samples of the leukemia patients' sera and 1 of the 4 samples of the prostatic cancer patients' sera. SP1 detection rates and concentrations appeared to increase in the sera of cervical carcinoma and leukemia patients in accordance with the progress of the diseases. SP1 concentrations in the sera of women in early pregnancy were not correlative to measured E2 and E3 concentrations in the same samples, but there was a significant correlation with progesterone and HCG concentrations. The RIA method for measuring SP1, which we have established, is available for measuring SP1 in the low concentration range. The method is expected to be applied clinically, such as in examinations in early pregnancy, and will be available in fundamental studies such as attempts to measure the SP1 movement in malignant tumour patients, in cooperation with studies of the meaning of SP1 production at pregnancy.