Since cortisol (F) can influence fetal lung maturation in late gestation, interconversion between cortisol and its inactive analogue cortisone (E), catalyzed by 11(beta)-hydroxysteroid dehydrogenase (11-HSD) (E.C.1.1.1.146), may be an important mechanism for controlling the level of F in the fetal lung parenchyma. The objects of this study were to: (1) resolve conflicting data; and (2) to study possible regulating factors of the 11-HSD. Human fetal lungs (HFL) of gestational ages 9-20 weeks were grown as monolayer cultures or as explants with ('3)H-F and ('3)H-E or ('14)C-E (0.01-17 ng/ml), for 6-16 days. Extracts of tissue culture medium were chromatographed to separate the steroids, and the per cent conversion was calculated. From the differences observed between explant and monolayer cultures it was concluded that: (1) the E to F activity observed in midgestational HFL monolayer cultures is an artefact of the culture system and is therefore not physiological, thus resolving the conflicting data; (2) F to E activity predominates in midgestational HFL and resides in undifferentiated epithelial cells; and (3) the 11-HSD in fibroblast-like cells is a different enzyme from the 11-HSD in HFL epithelial cells. These studies suggest that a decrease in the epithelial cell enzyme activity, elevating intracellular F levels at term, may be critically involved in maturation of the HFL.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.71815 |
| Date | January 1983 |
| Creators | Abramovitz, Mark. |
| 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 (Division of Experimental Medicine.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 000176194, proquestno: AAINK64417, Theses scanned by UMI/ProQuest. |
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