Prolonged, intravenous paraquat infusion in the rat. II. Paraquat-induced alterations in lung polyamine metabolism.
The effects of paraquat (PQ) on lung putrescine, spermidine, and spermine levels, and ornithine decarboxylase (ODC) activity were assessed in rats after 7 days of iv infusion of the herbicide via osmotic minipump. Paraquat administration at a rate of 250 nmol/hr [673 +/- 40 nmol/kg/hr (n = 15)] had no effect on these parameters. In contrast, significant (p less than 0.05) elevations in lung putrescine (407% of control), spermidine (202% of control), and ODC activity (174% of control were measured in lungs of rats given 500 nmol PQ/hr [1.31 +/- 0.53 mumol/kg/hr (n = 14)]. Since evidence of lung damage was, likewise, observed only in the high-dose PQ rats, these changes in polyamine metabolism could have been a nonspecific response to PQ-induced lung injury rather than a direct biochemical effect of PQ. The results suggest that stimulation of polyamine biosynthesis may play an important role in PQ-induced lung injury. This role may involve regulation of repair mechanisms or, conversely, the polyamines may actually mediate PQ-induced fibrotic changes in the lung.
Dunbar
J R
JR
Department of Surgery, Quillen-Dishner College of Medicine, East Tennessee State University, Johnson City 37614.
DeLucia
A J
AJ
Acuff
R V
RV
Ferslew
K E
KE
D000818:Animals; D008168:Lung / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D009955:Ornithine Decarboxylase / Q000378:metabolism; D010269:Paraquat / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000633:toxicity; D011073:Polyamines / Q000378:metabolism*; D011700:Putrescine / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013095:Spermidine / Q000378:metabolism; D013096:Spermine / Q000378:metabolism
D011073:Polyamines; D013096:Spermine; D009955:Ornithine Decarboxylase; D010269:Paraquat; D013095:Spermidine; D011700:Putrescine