Radioimmunoassay of Human Chorionic Somatomammotropin in Serum, Amniotic Fluid, and Urine

Abstract

A method is described for measurement of human chorionic somatomammotropin (HCS) by use of a double-antibody technique, for concentrations ranging from 2 ng/ml to 20 µg/ml. The cross-reactive characteristics of rabbit anti-human HCS serum No. CT 3399 from NIAMD are explored. A dilution plan is presented utilizing a standard curve from 0.75 to 80 ng/ml. Concentrations (mean and ranges) for HCS in maternal serum (evaluated every four weeks during pregnancy), umbilical cord serum, serum from babies, amniotic fluid, and urine are given.

Human Placental Lactogen (HPL) Levels in Amniotic Fluid

“…The mean level of H PL found in amn iotic fluid in our patient with normal pregnancy is comparable with those previously reported (6)(7)(8)10). It is about 10 % of the respective serum level.…”

“…Although the HPL level in maternal blood has been the subject of many investigations ( 1-5), little is known about the HPL concentrations in the relatively inaccessible amniotic fluid. The mean HPL level in amniotic fluid at term is found to be 0.50 ILg/ml (6), 0.55/Lg/ml (7) or 0.76 /Lg/mt (8). A positive correlation with the corresponding serum value is reported by some groups of investigators (7,9,10) and an increasing trend with advancing gestational age by Grumbach and his co-workers (6).…”

“…A positive correlation with the corresponding serum value is reported by some groups of investigators (7,9,10) and an increasing trend with advancing gestational age by Grumbach and his co-workers (6). However, the number of HPL samples has been relatively small, ranging from 8 (8) to 52 ( 10).…”