Evidence for a vitamin d paracrine system regulating the maturation
of the developing rat lung epithelium.
Nguyen, T. M., H. Guillozo, L. Marin, C. Tordet, S. Koite, M.
Garabedian.
C.N.R.S URA 583, H[circumflex]opital Saint Vincent de Paul, Paris,
France
APStracts 3:0059L, 1996.
Rat fetal lung is a target tissue for 1,25-(OH)2D3. We have identified
the cells that respond to the hormone and tested the hypothesis that
the lung is also a source of 1,25-(OH)2D3. We found that: 1) at the
end of pregnancy (days 20-21) type II pneumocytes bore 1,25-(OH)2D3
receptors and responded to the hormone. Incubating these cells with
10-9M 1,25-(OH)2D3 for 48 h stimulated the synthesis (+ 87.3 +/- 9.1
%) and release (+ 61.7 +/- 6.1 %) of disaturated phosphatidylcholine
; -2) EB 1213, a 1,25-(OH)2D3 analog with low calcemic activity, had
similar effects on type II pneumocytes; -3) neither fetal lung
fibroblasts, nor neonatal type II pneumocytes (day 2 post-partum)
expressed 1,25-(OH)2D3 receptors; - 4) in contrast, fetal lung
fibroblasts taken on days 19-22 of gestation converted 3H 25-(OH)D3
to 3H 1,25-(OH)2D3, while type II pneumocytes and skin fibroblasts
did not. These findings suggest that 1,25-(OH)2D3 is a local mediator
of epithelial: mesenchymal cell interactions in the developing rat
lung, and that 1,25-(OH)2D3 or EB 1213 might be therapeutically
useful in treating the respiratory distress syndrome of premature
neonates.
Received 5 April 1995; accepted in final form 8 April 1996.
APS Manuscript Number L105-5.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 1 May 96