Effects of poly I: poly C on rat pulmonary and hepatic cytochromes P-450 and b5.
Interferon inducing agents such as poly I:poly C have been shown to reduce the hepatic hemoproteins cytochromes P-450 and b5 along with the associated monooxygenase activities [el Azhary and Mannering, Molec. Pharmac. 15, 698 (1979)]. In a previous study [Kikkawa et al., Lab. Invest. 50, 62 (1984)], we demonstrated that the interferon inducing agent poly I:poly C reduces pulmonary microsomal hemoprotein by 50% when administered to rats. The current investigation was conducted to characterize these changes in more detail and compare them to analogous changes in the liver. Compared to controls, cytochrome P-450 in both the lungs and livers of poly I:poly C treated rats declined by 40% at 24 hr and 55% at 48 hr (P less than 0.01). By 72 hr the decline was only 25%. In contrast, cytochrome b5 levels declined by less than 30% of control values during the first 48 hr following poly I:poly C injection (P less than 0.01) and returned to control levels by 72 hr. These changes in both cytochrome P-450 and b5 were reflected in decreases in pulmonary microsomal hemoprotein. Benzphetamine-N-demethylase activity declined by 45% in lung microsomes at 48 hr (P less than 0.01) after injection of poly I:poly C, while 7-ethoxycoumarin-O-deethylase (P less than 0.05) and 7-ethoxyresorufin-O-deethylase activities declined by approximately 41%. In the liver from these same poly I:poly C treated groups, benzphetamine-N-demethylase declined by 66% (P less than 0.05), while 7-ethoxycoumarin-O-deethylase and 7-ethoxyresorufin-O-deethylase activities declined by 60% (P less than 0.02 and P less than 0.05 respectively).
Mettler
N R
NR
Department of Pathology, New York Medical College, Valhalla 10595.
Yano
S
S
Kikkawa
Y
Y
D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D003573:Cytochrome b Group / Q000378:metabolism*; D015786:Cytochromes b5; D006418:Heme / Q000032:analysis; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D008168:Lung / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D011070:Poly I-C / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D003573:Cytochrome b Group; D006418:Heme; D015786:Cytochromes b5; D003577:Cytochrome P-450 Enzyme System; D011070:Poly I-C