L-triiodothyronine (T/sub 3/) enhances lung surfactant phospholipid flux in rabbit fetus
The effect of thyroid hormone on surfactant phospholipid production in fetal lung was studied by simultaneously measuring the surfactant phosphatidylcholine (PC) content and its turnover in lamellar body and alveolar lavage fractions. Pregnant New Zealand white rabbits of 27 days' gestation were properly anesthetized and the uterus opened by a midline incision. Each fetus in each litter was injected with T/sub 3/ along with (/sup 14/C)-palmitate and (/sup 3/H)-choline. Control fetuses were injected with saline instead of T/sub 3/. PC was isolated from lamellar body and lung lavage from each fetus. Zilversmit equations for a two-compartment precursor-product model was used to analyze specific activity versus time curves and the turnover times for surfactant PC. Fluxes of surfactant PC were then calculated from its turnover times and pool sizes. The biological half-life for (/sup 14/C)-palmitate and (/sup 3/H)-choline labeled PC did not change by T/sub 3/ treatment. Turnover times for labeled palmitate and choline were 9.2 hr and 10.0 hr, respectively, for normal fetus and 6.0 hr and 5.8 hr, respectively, for T/sub 3/-treated fetus. While the pool size of PC recovered by the alveolar wash did not change significantly, T/sub 3/ enhanced the flux of this phospholipid from the lamellar bodies into alveolar space by 1.7 times within 4 hr. These results suggest that thyroid hormone may promote fetal lung development by enhancing the release of surfactant into the alveolar space.
- Research Organization:
- Long Island Jewish-Hillside Medical Center, New Hyde Park, NY
- OSTI ID:
- 5207700
- Report Number(s):
- CONF-8606151-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 45:6; ISSN FEPRA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
ALCOHOLS
AMINES
AMMONIUM COMPOUNDS
ANIMALS
BIOLOGICAL EFFECTS
BIOLOGICAL HALF-LIFE
BODY
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CHOLINE
DRUGS
EQUATIONS
ESTERS
FEMALE GENITALS
FETUSES
HEXADECANOIC ACID
HORMONES
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LAVAGE
LIPIDS
LIPOTROPIC FACTORS
LUNGS
MAMMALS
MATHEMATICAL MODELS
MONOCARBOXYLIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANS
PEPTIDE HORMONES
PHOSPHOLIPIDS
QUATERNARY COMPOUNDS
RABBITS
RESPIRATORY SYSTEM
SECRETION
SURFACTANTS
THYROID HORMONES
TRACER TECHNIQUES
TRITIUM COMPOUNDS
UTERUS
VERTEBRATES