Mass Spectrometric and Immunologic Detection of Prolactin-Derived Vasoinhibin in Human Serum.

Background: Circulating levels of the antiangiogenic protein, vasoinhibin, derived from the proteolytic cleavage of prolactin (PRL), in prolactinoma are unknown, as is the molecular nature of its isoforms. Dimerization of recombinant vasoinhibin has been reported.

Methods: Vasoinhibin in a human serum sample was identified by using preparative electrophoresis with subsequent SDS-PAGE and Western blot analysis, as well as mass spectrometry (MS) and ELISA.

Human Placental Tissue Contains A Placental Lactogen-Derived Vasoinhibin.

Hormonal factors affecting the vascular adaptions of the uteroplacental unit in noncomplicated and complicated pregnancies are of interest. Here, 4 human placentas from women with and without preeclampsia (PE) were investigated for the presence of placental lactogen (PL)-derived, antiangiogenic vasoinhibin. Western blotting and mass spectrometry of placental tissue revealed the presence of a 9-kDa PL-derived vasoinhibin, the normal 22-kDa full-length PL, and a 28-kDa immunoreactive protein of undetermined nature.

Plasmin generates vasoinhibin-like peptides by cleaving prolactin and placental lactogen.

Vasoinhibin is an antiangiogenic, profibrinolytic peptide generated by the proteolytic cleavage of the pituitary hormone prolactin by cathepsin D, matrix metalloproteinases, and bone morphogenetic protein-1. Vasoinhibin can also be generated when placental lactogen or growth hormone are enzymatically cleaved. Here, it is investigated whether plasmin cleaves human prolactin and placental lactogen to generate vasoinhibin-like peptides.