Chronic idiopathic polyhydramnios: evidence for a defect in the chorion laeve receptor for lactogenic hormones.

Binding of human GH (hGH) to the lactogenic receptor of human chorion laeve has been compared in membrane preparations from normal pregnancies and those complicated by chronic idiopathic polyhydramnios. Specific binding of [125I]hGH was significantly lower (mean +/- SE, 1.64 +/- 0.28%; n = 5) in chronic idiopathic polyhydramnios than in normal pregnancies (2.93 +/- 0.4%; n = 16). Scatchard analysis data were consistent with a reduced lactogenic hormone receptor concentration being the explanation for this reduced hGH binding. By contrast, the specific binding of [125I]insulin to its receptor was unchanged when chorion laeve from hydramniotic pregnancies (7.29 +/- 1.98%; n = 4) was compared with that from normal pregnancies (8.63 +/- 1.35%; n = 7). We conclude that a lactogenic hormone receptor defect exists in the chorion laeve of pregnancies complicated by chronic idiopathic polyhydramnios. Such impaired binding for PRL may explain the development of excessive amniotic fluid volumes, which is characteristic of this complication of pregnancy.