Changes in nucleic acid and protein levels in atrophying skeletal muscle in cancer cachexia.
BACKGROUND
To investigate factors responsible for muscle loss in cachexia changes in nucleic acid and protein levels have been determined and compared with those induced by a tumour-produced cachectic factor, proteolysis-inducing factor (PIF).


METHODS
Mice were transplanted with the MAC16 tumour, while non-tumour bearing mice received PIF (1.5 mg/kg; i.v.) over a 24 h period.


RESULTS
There was an exponential decrease in RNA and protein in gastrocnemius muscle with weight loss without an effect on the DNA content. Levels of myosin followed the decrease in total protein, while actin levels remained constant. There was also a significant loss of protein from soleus muscle and spleen, but not from heart, liver and kidney. PIF also produced a significant loss of RNA and protein in spleen and reduced the protein content of soleus muscle.


CONCLUSIONS
This suggests that PIF may be responsible for changes in protein and RNA content of tissues with the development of cachexia.
Bhogal
Ameek S
AS
Biomedical Science, School of Life and Health Sciences, Aston University, Birmingham, B4 7ET, UK.
Lorite
Maria L
ML
Tisdale
Michael J
MJ
D000818:Animals; D002100:Cachexia / Q000209:etiology / Q000378:metabolism*; D004247:DNA / Q000378:metabolism*; D008297:Male; D051379:Mice; D009124:Muscle Proteins / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D009374:Neoplasms, Experimental / Q000150:complications / Q000378:metabolism*; D012313:RNA / Q000378:metabolism*
D009124:Muscle Proteins; D012313:RNA; D004247:DNA