Human chorion laeve contains a lactogenic
hormone [
prolactin (PRL),
growth hormone (GH) and
placental lactogen (hPL)] receptor. Here, we studied binding of the potent lactogen, human GH, to this receptor in 18 normal pregnant women, in 12 patients whose pregnancies were complicated by chronic
polyhydramnios and in 13 with chronic
oligohydramnios.
Polyhydramnios was classified clinically as idiopathic in seven patients, and secondary and associated with various disorders in the remaining five patients. Lactogenic
hormone binding was lower in association with
polyhydramnios (mean 1.60, SEM 0.15%) than with normal amniotic fluid volume (mean 3.05, SEM 0.40%; P less than 0.05); Scatchard analysis indicated that a reduced number of
lactogen receptors within the chorion laeve was the reason. The lactogenic
hormone receptor defect in the chorion laeve was present in pregnancies complicated by either idiopathic or secondary
polyhydramnios. In contrast to chronic
polyhydramnios, tissue from patients with chronic
oligohydramnios bound lactogenic
ligands in a normal fashion.
Insulin binding sites were also identified in the chorion laeve, and, in contrast to the lactogens, binding parameters were equivalent in the three patient groups. PRL resistance developing subsequent to this chorion laeve receptor defect might produce the excessive amniotic fluid volume characteristic of
polyhydramnios. We propose that a chorionic PRL receptor deficiency underlies the various clinical forms of chronic
polyhydramnios.