title: Pregnancy-associated plasma protein A in human ovarian follicular fluid.
abstract: Human ovarian follicular fluid contains pregnancy-associated plasma protein A (PAPP-A) immunoreactivity as detected by RIA. This PAPP-A was found to be stable to repeated freeze-thaw cycles and not removed by dialysis. Further characterization showed that ovarian follicular PAPP-A bound reversibly to heparin-Sepharose. On gel chromatography follicular PAPP-A coeluted with radioiodinated PAPP-A and pregnancy serum PAPP-A which was determined to have an apparent mol wt of 820,000. In the RIA, serial dilutions of high molecular weight heparin-Sepharose binding proteins gave parallel displacement curves to pooled late pregnancy serum and to the International Reference Preparation, WHO 78/610. All the human ovarian follicular fluids tested had PAPP-A concentrations between 0.317-1.595 IU/liter. The relationship between follicular content of PAPP-A and follicular volume was best expressed by the exponential relationship, y = 164.3 e0.117x. Therefore, ovarian follicular fluid PAPP-A has many physico-chemical similarities to and shares immunological identity with pregnancy-derived PAPP-A. As this pregnancy-associated glycoprotein cannot be detected in the circulation of normal non-pregnant adults, its presence within the Graafian follicle is believed to be of intrafollicular origin for the maintenance of proteolytic homeostasis.
mesh_terms: D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D006080:Ovarian Follicle / Q000378:metabolism*; D011257:Pregnancy Proteins / Q000378:metabolism*; D011266:Pregnancy-Associated Plasma Protein-A / Q000378:metabolism*
chemical_list: D007457:Iodine Radioisotopes; D011257:Pregnancy Proteins; D011266:Pregnancy-Associated Plasma Protein-A