Down-regulation of liver RNA breakdown by turpentine administration in the starved rat: autophagy and relevant factors.
OBJECTIVE
To determine whether the inhibition of RNA breakdown observed in ad libitum fed rats 24 h after turpentine administration still occurs in inflamed rats fasted for 24 h and to examine the mechanism and factors involved.


METHODS
RNA breakdown was measured during cyclic in situ perfusion of livers by the accumulation of [14C] cytidine after in vivo RNA labelling. Autophagic activity was determined by the morphometric analysis of lysosomal structures.


RESULTS
The decrease in RNA breakdown (53%) observed in the inflamed rats was accompanied by a 38% drop in the fractional cytoplasmic volume of initial and digestive autophagic vacuoles. Among amino acids, only the portal levels of glutamate were significantly enhanced by 83%. In vivo suppression of glucocorticoid activity using RU 38486 in inflamed rats did not affect the inhibition of RNA breakdown.


CONCLUSIONS
The results show that turpentine-induced inflammation in fasted rats inhibits RNA degradation as well as autophagy and that glucocorticoids do not seem to be involved.
Saadane
A
A
Laboratoire de Biologie Cellulaire, U 327 de l'Institut National de la Santé de la Recherche Médicale (INSERM), Faculté de Médecine Xavier Bichat, Université Paris 7, France.
Delautier
D
D
Lestriez
V
V
Feldmann
G
G
Lardeux
B
B
Bleiberg-Daniel
F
F
D000208:Acute Disease; D000818:Animals; D015536:Down-Regulation; D007249:Inflammation / Q000139:chemically induced / Q000378:metabolism*; D008099:Liver / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D015735:Mifepristone / Q000494:pharmacology; D010477:Perfusion; D012313:RNA / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011965:Receptors, Glucocorticoid / Q000037:antagonists & inhibitors; D013217:Starvation; D014425:Turpentine / Q000494:pharmacology*
D011965:Receptors, Glucocorticoid; D015735:Mifepristone; D012313:RNA; D014425:Turpentine