The effects of various steroid hormones on human chorionic gonadotropin (hCG) production and placental viability were investigated using an explant culture model of human placenta. / Placental hCG production was assessed using two different methods: (a) hCG concentrations in media recovered from cultures were measured by radioimmunoassay and (b) tissue levels of hCG in cultured placentae were determined immunohistochemically; both were evaluated before and after exposure to steroid hormones. In first trimester placentae, progesterone and dehydroepiandrosterone (DHEA) increased hCG concentrations both in collected medium and levels in cultured placentae. Estradiol increased the levels of hCG in tissues but not in media. Cortisol increased concentrations in media but did not alter tissue levels. Testosterone decreased hCG levels in media, but had no effect on hCG placental content. In third trimester cultures, progesterone and DHEA were the only hormones studied which increased concentrations of hCG in media; estradiol, cortisol and testosterone had no effect. Progesterone, estradiol and DHEA, alone or in combination, extended the viability of first trimester placental explant cultures from approximately 7 to 30 days. There was a significant relationship between placental viability and tissue hCG levels (r = 0.73, P $<$ 0.001). The concentrations of hCG, progesterone and estradiol in human placentae were determined at various times through gestation. These studies suggest that a temporal relationship exists between the placental levels of hCG and these steroids, and that they may be significant determinants of growth and differentiation of the placenta in vivo. Furthermore, these investigations support the hypothesis that hCG production by the placenta is subject to paracrine regulation by steroid hormones.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.74342 |
| Date | January 1989 |
| Creators | Ahmed, Najma Ayesha |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Physiology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001232606, proquestno: AAINN63703, Theses scanned by UMI/ProQuest. |
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