Adrenal-seminal-pituitary protein levels in maternal serum and amniotic fluid.

Adrenal-seminal-pituitary protein (ASP) was measured by radioimmunoassay in maternal serum and amniotic fluid samples obtained throughout pregnancy. Levels of ASP in maternal circulation showed a steady rise from a mean of 350 micrograms/l at ten weeks gestation to 526 micrograms/l at term. There was a further rise in ASP levels during labour. In contrast, a slight decline in amniotic fluid ASP was observed throughout pregnancy but the levels rose sharply during labour. These findings are in agreement with the hypothesis that ASP is closely associated with prostaglandin physiology.