Effects of dexamethasone on lung protein turnover.
Dexamethasone (2.5 mg/day per kg) treatment of young growing rats resulted in reduced food intake and rapidly inhibited whole-body and lung growth. Although the reduction in food intake partially explained the decrease in whole-body growth, it did not influence lung growth. After 24 h of dexamethasone treatment, ribosomal efficiency in the lung was reduced 44%, producing a 38% decrease in the rate of pulmonary protein synthesis. Extending dexamethasone treatment to 5 days resulted in decreases in both ribosomal efficiency (35%) and capacity (28%), explaining the 53% reduction in lung protein synthesis at this time. After both the acute and chronic steroid regimes, the decreased rates of pulmonary protein synthesis were accompanied by a loss of polyribosomes and an elevated ribosomal monomer pool, indicating that dexamethasone blocked translation at the site of peptide-chain initiation.
Fussell
J C
JC
School of Biochemical and Physiological Sciences, University of Southampton, U.K.
Kelly
F J
FJ
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D003907:Dexamethasone / Q000494:pharmacology*; D004435:Eating / Q000187:drug effects; D008168:Lung / Q000187:drug effects* / Q000254:growth & development; D008297:Male; D009929:Organ Size / Q000187:drug effects; D014176:Protein Biosynthesis; D011500:Protein Synthesis Inhibitors; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012270:Ribosomes / Q000187:drug effects
D011500:Protein Synthesis Inhibitors; D011506:Proteins; D003907:Dexamethasone