title: The developing rat lung fibroblast and alveolar type II cell actively recruit surfactant phospholipid substrate.
abstract: Timely, adequate production of pulmonary surfactant is critical for survival at birth. This process is dependent on both maternal nutrition and glucocorticoids. Fetal rat lung lipofibroblast triglyceride accumulation is saturable, temperature-dependent and stimulated by glucocorticoids and cyclic AMP in primary cell culture. Spontaneous triglyceride uptake by fibroblasts increases ninefold between 17 and 21 days (= term) gestation and is stimulated 30-80% by exogenous glucocorticoid treatment. Coculture of Type II cells with fibroblasts preloaded with 3H-trioleate and increasing amounts of triglyceride results in a concomitant increase in saturated phosphatidylcholine (SPC) synthesized by Type II cells. Dexamethasone stimulates mobilization of fibroblast triglyceride incorporation into Type II cell-SPC by 36-40%. The hormonally regulated uptake and mobilization of triglyceride suggest active recruitment of surfactant phospholipid substrate by both alveolar connective tissue and epithelial cells.
authors.affiliation: Department of Pediatrics, University of Maryland Medical School, Baltimore, MD 21201, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Nunez
authors.forename: J S
authors.initials: JS
authors.lastname: Torday
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology; D005314:Embryonic and Fetal Development; D005347:Fibroblasts / Q000378:metabolism; D008168:Lung / Q000196:embryology* / Q000378:metabolism / Q000502:physiology; D010743:Phospholipids / Q000378:metabolism; D011650:Pulmonary Alveoli / Q000378:metabolism* / Q000502:physiology; D011663:Pulmonary Surfactants / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014304:Triolein / Q000378:metabolism*
chemical_list: D010743:Phospholipids; D011663:Pulmonary Surfactants; D014304:Triolein; D003907:Dexamethasone