Induction of the "pregnancy zone" protein by conjugated oestrogens.

Treatment with conjugated oestrogens was found to increase significantly the serum concentration of the pregnancy zone protein (PZ) in a group of postmenopausal women. The basic level of PZ before treatment was comparatively high in this group of women and might be related to age and previous pregnancies. Naturally occurring conjugated oestrogens have a similar effect on the induction of PZ as synthetic oestrogens.