Effects of starvation and diabetes on protein synthesis in lung.
Metabolism of lung proteins was investigated in rats starved 3 days or made diabetic with streptozotocin. Body weight was below normal in both groups, but lung weight decreased only in starved animals. Total lung protein and RNA (mg/lung) decreased during starvation and diabetes. Protein concentration (mg/g) was unchanged in either group of animals; RNA concentration decreased only during starvation. Protein synthesis, estimated in lungs perfused in situ, was reduced 22% in starvation, but remained unchanged in diabetes. Inhibition of protein synthesis was accounted for by loss of RNA. Ribosomal profiles were unchanged by starvation, suggesting an unaltered relationship between rates of peptide-chain initiation and elongation in vivo. Activity of an eIF-2-like initiation factor decreased during starvation in proportion to the loss of RNA. In diabetes, factor activity remained normal. Thus, starvation but not streptozotocin-induced diabetes, reduced the capacity of the lung to synthesize protein. No evidence for reduced efficiency of synthesis was observed.
D000818:Animals; D001835:Body Weight; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D008168:Lung / Q000033:anatomy & histology / Q000378:metabolism*; D008297:Male; D009929:Organ Size; D010448:Peptide Initiation Factors / Q000378:metabolism; D014176:Protein Biosynthesis; D012313:RNA / Q000378:metabolism; D012343:RNA, Transfer / Q000378:metabolism; D051381:Rats; D013217:Starvation / Q000378:metabolism*; D013311:Streptozocin
D010448:Peptide Initiation Factors; D013311:Streptozocin; D012313:RNA; D012343:RNA, Transfer