Abstract
ABSTRACT: Transforming growth factor-α (TGF-α) is a structural homologue of epidermal growth factor and competes for binding on a common transmembrane protein receptor/kinase. Although TGF-α appears to be more important than epidermal growth factor in embryogenesis and mammalian organogenesis, there is little information regarding its expression in developing lung. Accordingly, we measured levels of immunoreactive TGF-α and its gene expression in late-term fetal rat lung during the transition from the canalicular (19–20 d) to the saccular (21 d) stage. We report that at 19 d gestation intrapulmonary levels of TGF-a were 1.4 ± 0.3 pmol/mg protein as determined by RIA, but had decreased by 50% at 21 d. To determine if the TGF-α gene is expressed in lung, RNA isolated from fetal rat lung was reverse transcribed, and a 302-bp fragment corresponding to a portion of the TGF-α gene was amplified by polymerase chain reaction. Southern blot hybridization with a 32P-labeled 2.3-kb EcoRI fragment of rat TGF-α cDNA clone showed a pattern of declining expression during late gestation. Therefore, fetal rat lung expresses TGF-α, as is evidenced by the synthesis of both the message and the protein. Because levels of protein were highest in the period of canalicular lung development when the respiratory acinus is formed and vascularized, a potential role for this intrapulmonary growth factor in pulmonary remodeling is suggested.
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Kubiak, J., Mitra, M., Steve, A. et al. Transforming Growth Factor-α Gene Expression in Late-Gestation Fetal Rat Lung. Pediatr Res 31, 286–290 (1992). https://doi.org/10.1203/00006450-199203000-00019
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DOI: https://doi.org/10.1203/00006450-199203000-00019
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