Abstract
Keratinocyte growth factor (KGF, FGF-7) is a potent mitogen for epithelial cells. We instilled recombinant human KGF to determine the effects of KGF on alveolar epithelial cells. Left lungs of adult rats were instilled intrabronchially with KGF (5 mg/kg) or normal saline. KGF instillation resulted in epithelial cell hyperplasia, and the alveolar bromodeoxyuridine (BrdU) labeling index peaked at 35% on day 2 after instillation. The mRNA levels for the surfactant proteins (SPs) SP-A, SP-B, and SP-D were increased in whole lung tissue on days 1 and 2 after KGF treatment and then returned to control levels on days 3-7. SP-C mRNA levels were increased on days 2-5 after KGF instillation. However, all surfactant protein mRNAs were reduced in type II cells isolated from rats instilled with KGF 2 or 3 days before isolation. These observations were confirmed by in situ hybridization. Instillation of KGF also increased the amount of SP-A and SP-D in lavage fluid. Transcripts for CC10, the 10-kDa Clara cell protein, were decreased. KGF increases the mRNA for the surfactant proteins per lung because of type II cell hyperplasia, but the mRNA per cell is slightly diminished as measured in isolated cells or estimated by in situ hybridization.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Age Factors
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Animals
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Bromodeoxyuridine / analysis
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Bronchoalveolar Lavage Fluid / chemistry
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Cell Division / drug effects
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Epithelial Cells / chemistry
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Epithelial Cells / cytology*
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Epithelial Cells / drug effects
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Fibroblast Growth Factor 10
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Fibroblast Growth Factor 7
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Fibroblast Growth Factors*
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Gene Expression / drug effects
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Glycoproteins / analysis
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Glycoproteins / genetics
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Growth Substances / pharmacology*
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Humans
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In Situ Hybridization
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Nuclear Proteins / genetics
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Proteins / genetics
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Proteolipids / analysis
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Proteolipids / genetics*
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Pulmonary Alveoli / chemistry
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Pulmonary Alveoli / cytology*
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Pulmonary Alveoli / physiology
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Pulmonary Surfactant-Associated Protein A
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Pulmonary Surfactant-Associated Protein D
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Pulmonary Surfactant-Associated Proteins
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Pulmonary Surfactants / analysis
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Pulmonary Surfactants / genetics*
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RNA, Messenger / analysis
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Rats
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Rats, Inbred F344
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Respiratory Mucosa / chemistry
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Respiratory Mucosa / cytology*
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Respiratory Mucosa / physiology
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Specific Pathogen-Free Organisms
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Thyroid Nuclear Factor 1
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Transcription Factors / genetics
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Uteroglobin*
Substances
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FGF10 protein, human
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FGF7 protein, human
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Fgf10 protein, rat
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Fgf7 protein, rat
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Fibroblast Growth Factor 10
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Glycoproteins
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Growth Substances
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Nuclear Proteins
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Proteins
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Proteolipids
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Pulmonary Surfactant-Associated Protein A
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Pulmonary Surfactant-Associated Protein D
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Pulmonary Surfactant-Associated Proteins
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Pulmonary Surfactants
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RNA, Messenger
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SCGB1A1 protein, human
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Scgb1a1 protein, rat
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Thyroid Nuclear Factor 1
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Transcription Factors
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Fibroblast Growth Factor 7
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Fibroblast Growth Factors
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Uteroglobin
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Bromodeoxyuridine