Amniotic Fluid Reactivity Detected by Somatomedin C Radioreceptor Assay: Correlation With Growth Hormone, Prolactin and Fetal Renal Maturation

Abstract

Amniotic fluid was assayed by a radioreceptor assay utilizing 125I-somatomedin C and placental membranes. Growth hormone and prolactin levels were measured by radioimmunoassay at different gestational ages (8-41 weeks). Somatomedin receptor activity, growth hormone, and prolactin reached high levels during early gestation (8-26 weeks) displaying different patterns of appearance which reflect fetal serum levels of these hormones. After 26 weeks gestation all these hormones decreased in concentration. This decrease showed a strong correlation with fetal renal maturation as measured by amniotic fluid creatinine levels.

Further Evidence of Prolactin Production from Human Decidua and Its Transport across Fetal Membrane

“…8]. The results of the present study also seem to support the negative view on the ground that the amniotic fluid level of PRL did not show any correlation with its level in either the maternal or fetal blood and that in spite of the view of Chochinov et al [6] that PRL may be transferred into the urine and further into the amniotic fluid through the immature kidneys of fetuses, the urine level of PRL in newborns irrespective of sex was found to be very low. Therefore, the view for fetal origin is not convincing.…”

“…The con centration of PRL in the amniotic fluid be gins to increase in the early stage of pregnan cy, reaches a peak in the middle of gestation, then decreases gradually [2,6,8,16], whereas the blood level of PRL in pregnant women and fetuses increases as pregnancy progresses and reaches a peak in the late stage of preg nancy [ 1,2,8,17], The bromocriptine inhibi tion of the PRL production in the pituitary of mother and fetus causes no change in the amniotic fluid level of PRL [18]. The exci sion of the pituitary from pregnant rhesus monkeys or the fetal death in utero does not induce changes in the amniotic fluid level of PRL [19].…”

“…Its origin has been controversial up to date. Three hy potheses have been proposed as the origin, namely the pituitary of the mother [4,5], that of the fetus [6,7] and the human decidua hypertrophied during pregnancy [8][9][10][11][12]. A brief review of the studies which have been reported until now suggests that many inves tigators recently support such a view that PRL, as produced in the decidua and secreted therefrom, is transported into the amniotic fluid to be found there [9][10][11][12][13][14], The purpose of this study is to clarify whether or not the PRL in the amniotic fluid is of decidual origin.…”

Changes in the Concentration of Somatomedin‐like Activity in Amniotic Fluid and Maternal Plasma From Rhesus Monkeys During the Last Third of Gestation

“…In human amniotic fiuid bioreactive SLA has been reported to increase from very low concentrations, relative to serum, at 16-20 weeks to higher, but still very low, concentrations at term (Bala et al, 1978). Concentrations of immunoreactive somatomedin-C decrease during this time (Chochinov et al, 1976). This study covers a shorter period of pregnancy and it is possible that the concentrations of SLA in amniotic fiuid may vary during the first two-thirds of pregnancy.…”

“…INTRODUCTION SLA in amniotic fluid has been described by several investigators (Bala and Smith, 1976;Bala et al, 1978;Chochinov et al, 1976;Moberg et al, 1976;Franklin et al, 1979). In all these studies the amniotic fluid was of human origin and was obtained either at delivery or by amnioeentesis for various clinical conditions.…”