Gestational regulation of the gene expression of C-type natriuretic peptide in mouse reproductive and embryonic tissue

C-Type natriuretic peptide (CNP) is a vasoactive hormone and the endothelia l component of the natriuretic peptide system. We examined the expression o f CNP in mouse reproductive organs and embryos at different stages of gesta tion. Pregnant mice were killed and embryos were dissected on gestational d ays 9.5, 12.5, 15.5, 18.5 postconceptionem (pc) and at term. Nonpregnant mi ce were used as controls. Total RNA was isolated from placenta, ovaries, my ometrium and from head and trunk of embryos and neonates. CNP-mRNA was quan tified by ribonuclease-protection assay (RPA). Uterine CNP-mRNA concentrati ons increase during pregnancy up to the sevenfold concentration, whereas in the ovaries these levels decrease to 10% compared to nonpregnant controls. In the placenta, a peak of CNP expression has been observed around day 15. 5 pc, whereby placenta showed the strongest CNP signals. CNP-mRNA concentra tions in embryos are gestational age-dependent with a high level at day 9.5 pc in head and trunk. These results indicate that CNP has a regulatory fun ction in pregnancy and embryonic development. (C) 2001 Elsevier Science B.V . All rights reserved.