[Human chorionic somatommamotropins (HCS or HPL) : radioimmunologic determination and clinical significance].

The AA. have studied a new standardized radioimmunologic method for the routine determination of HCS. All the steps of the analysis have been studied, in particular those concerning the reability test and the precipitation of the complex with PEG. The best conditions were found when PEG 6000 is used at a concentration between 14-16 g in 100 ml (v/w), dissolved in veronal buffer, pH 7.4--9.4, with a dilution of protein (bovine serum) 1:4 in the incubation mixture. The reability test have given very good results. The c.p.m. of the analysis are plotted with a logit plot by computer which directly gives the values in ng/ml of the hormone in the plasma sample. The results obtained with this method are compared with those of the literature; the most striking difference in the present method appears in the last trimester of pregnancy in which the result have a low S.D. and can give a good help in clinical management of pregnant patients.