Nunez J S, Torday J S
Department of Pediatrics, University of Maryland Medical School, Baltimore, MD 21201, USA.
J Nutr. 1995 Jun;125(6 Suppl):1639S-1644S. doi: 10.1093/jn/125.suppl_6.1639S.
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.
及时、充足地产生肺表面活性物质对于出生时的存活至关重要。这个过程既依赖于母体营养，也依赖于糖皮质激素。在原代细胞培养中，胎鼠肺脂成纤维细胞甘油三酯的积累是可饱和的、温度依赖性的，并受到糖皮质激素和环磷酸腺苷的刺激。在妊娠17至21天（足月）之间，成纤维细胞自发摄取甘油三酯的量增加了9倍，外源性糖皮质激素治疗可刺激其增加30%至80%。将II型细胞与预先加载3H-油酸酯且甘油三酯含量不断增加的成纤维细胞共培养，会导致II型细胞合成的饱和磷脂酰胆碱（SPC）随之增加。地塞米松可刺激成纤维细胞甘油三酯掺入II型细胞-SPC的动员，增加36%至40%。激素调节的甘油三酯摄取和动员表明，肺泡结缔组织和上皮细胞都在积极募集表面活性物质磷脂底物。
