ATP and adenosine 3',5'-cyclic monophosphate stimulate the synthesis of surfactant protein A in rat lung.
Am J Physiol
; 264(5 Pt 1): L431-7, 1993 May.
Article
em En
| MEDLINE
| ID: mdl-8388646
ABSTRACT
Synthesis and secretion of surfactant protein A (SP-A) were studied in the isolated perfused rat lung using Trans35S-label (approximately 85% methionine, 15% cysteine) in the perfusate with or without 1 mM ATP or 0.1 mM 8-bromoadenosine 3',5',-cyclic monophosphate (8-BrcAMP) for up to 6 h of perfusion. By enzyme-linked immunosorbent assay, the SP-A content was 36 +/- 0.3% of total protein in extracellular surfactant and 10.8 +/- 1.9% of total protein in lamellar bodies of control lungs; these relativr proportions were maintained in the presence of ATP or 8-BrcAMP. Incorporation of [35S]methionine (cysteine) into the surfactant and lamellar body protein fraction could be detected at 4 h of perfusion. At 6 h, specific activity of total protein [disintegrations per minute (dpm)/micrograms)] was significantly increased in both the surfactant (54%) and lamellar body fractions (30%) under the influence of either secretagogue compared with control conditions. In the presence of ATP, there was a significant increase in the SP-A immunoprecipitable counts of 61 and 72% in extra- and intracellular compartments, respectively. However, no significant change was observed in the relative abundance of SP-A mRNA between control and secretagogue-treated lungs. This dissociation of SP-A mRNA abundance and label incorporation into protein indicates that alteration in translational efficiency or posttranslational factors may be involved in the secretagogue-induced stimulation of SP-A synthesis.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteolipídeos
/
Surfactantes Pulmonares
/
8-Bromo Monofosfato de Adenosina Cíclica
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Trifosfato de Adenosina
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AMP Cíclico
/
Pulmão
Limite:
Animals
Idioma:
En
Revista:
Am J Physiol
Ano de publicação:
1993
Tipo de documento:
Article