title: Placental calcitriol synthesis and IGF-I levels in normal and preeclamptic pregnancies.
abstract: Placenta is an extrarenal source of calcitriol and pregnancy is associated with increased maternal serum levels of this hormone. It has been reported that insulin-like growth factor I (IGF-I) stimulates placental calcitriol synthesis and that circulating levels of both hormones are low in preeclampsia. Since calcitriol production has not been determined in placental homogenates in preeclampsia, the aim of the present study was to establish if placental calcitriol synthesis and IGF-I concentration are altered in this tissue obtained from preeclamptic pregnancies. Placental samples were obtained from 8 preeclamptic (PE group) and 8 normotensive (NT group) pregnant women. Calcitriol synthesis was determined using [(3)H]-25(OH)D3 (2.94nM) as precursor and [(3)H]-1,25(OH)2D3 produced was calculated as the percentage of radioactivity co-eluting with unlabelled 1,25(OH)2D3 after two successive high pressure liquid chromatographies. Placental IGF-I levels were determined by RIA. In addition, maternal and umbilical calcitriol and IGF-I levels were also determined in these 2 groups using radioreceptor assay and RIA, respectively. The results of the present study showed that placentas from both groups were able to convert [(3)H]-25(OH)D3 into more polar metabolites. In the PE group, placental [(3)H]-1,25(OH)2D3 synthesis was significantly lower than in the NT group (19.6±6.2 vs 29.9±8.1fmoles/200mg wet weight, P=0.013). Regarding IGF-I, its levels were significantly lower in placentas of the PE group than in the NT group (15.2±3.9 vs 21.6±4.9ng/g wet weight, P=0.012). Maternal and umbilical calcitriol levels were significantly lower in the PE than in the NT group (P<0.001). In the PE group, serum IGF-I levels were significantly lower only in the maternal circulation (P<0.05). In conclusion, placental calcitriol synthesis and IGF-I levels are low in preeclampsia which may contribute to decreased local placental functions related to these two hormones and/or to decreased maternal and fetal pool of 1,25(OH)2D3 during preeclamptic pregnancies. This article is part of a Special Issue entitled '16th Vitamin D Workshop'.
authors.affiliation: Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan 14000, México, D.F., Mexico. Electronic address: ali.halhali@yahoo.com.mx.
authors.forename: Ali
authors.initials: A
authors.lastname: Halhali
authors.affiliation: Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan 14000, México, D.F., Mexico.
authors.forename: Lorenza
authors.initials: L
authors.lastname: Díaz
authors.affiliation: Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan 14000, México, D.F., Mexico.
authors.forename: David
authors.initials: D
authors.lastname: Barrera
authors.affiliation: Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan 14000, México, D.F., Mexico.
authors.forename: Euclides
authors.initials: E
authors.lastname: Avila
authors.affiliation: Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan 14000, México, D.F., Mexico.
authors.forename: Fernando
authors.initials: F
authors.lastname: Larrea
mesh_terms: D002117:Calcitriol / Q000378:metabolism*; D005260:Female; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D010920:Placenta / Q000378:metabolism*; D011225:Pre-Eclampsia / Q000378:metabolism*; D011247:Pregnancy
chemical_list: D007334:Insulin-Like Growth Factor I; D002117:Calcitriol
keywords: Calcitriol; IGF-I; Placenta; Preeclampsia; Vitamin D