Pregnancy-associated plasma protein-A (PAPP-A): concentration in uterine fluid and immunohistochemical localization in the endometrium.

Pregnancy-associated plasma protein-A (PAPP-A) was localized immunohistochemically in the endometrium and measured in uterine fluid of non-pregnant women. The variations of PAPP-A concentrations in uterine fluid during the menstrual cycle paralleled those found in the endometrium. In patients receiving hormone therapy there was a significant correlation between the uterine fluid PAPP-A concentration and the progestogen to oestrogen potency ratio of the hormonal treatment. The presence of PAPP-A in the uterine fluid cannot simply be explained by blood contamination or cell damage. These results are interpreted as indirect evidence for an exocrine as well as an endocrine secretion of PAPP-A by the endometrium which might be influenced by hormones.