Irgasan DP 300 (5-chloro-2-(2,4-dichlorophenoxy)-phenol) induces cytochrome P450s and inhibits haem biosynthesis in rat hepatocytes cultured on Matrigel.
1. The effect of Irgasan DP 300 (5-chloro-2-(2,4-dichlorophenoxy)phenol) on cytochrome P450 (P450) induction and haem biosynthesis was studied in rat hepatocytes cultured on Matrigel. 2. Irgasan DP 300 significantly induced 7-benzyloxyresorufin O-debenzylase activity, followed by 7-pentoxyresorufin O-depentylase and 7-ethoxyresorufin O-deethylase activities. 4-Nitrophenol hydroxylase, testosterone 6 beta-hydroxylase and methoxyresorufin O-demethylase activities were also slightly increased. The maximum induction of these enzyme activities was obtained at the same concentration of 125 microM in the culture medium. 3. Immunochemical blots using anti-rat cytochrome P450 antibodies revealed that Irgasan DP 300 preferably induced CYP2B1/2 along with a slight increase in 3A. These results indicate that Irgasan DP 300 is a phenobarbital-type inducer. 4. In the absence of exogenous 5-aminolevulinic acid (ALA), slight increases in protoporphyrin IX (2.6-fold) and coproporphyrin III (1.3-fold) were observed in the Irgasan DP 300-treated cultures. In contrast, when 75 microM ALA was present, Irgasan DP 300 (250 microM) caused an extensive accumulation of uroporphyrin I (13-fold). 5. Irgasan DP 300 inhibited rat hepatic uroporphyrinogen III synthase in vitro. 6. These results indicate that Irgasan DP 300 produced accumulation of hydroxymethylbilane in rat hepatocytes by inhibiting uroporphyrinogen III synthase, and consequently an accumulation of uroporphyrin I.
Jinno
H
H
Division of Environmental Chemistry, National Institute of Health Sciences, Tokyo, Japan.
Hanioka
N
N
Onodera
S
S
Nishimura
T
T
Ando
M
M
D000622:Aminolevulinic Acid / Q000494:pharmacology; D000818:Animals; D000891:Anti-Infective Agents, Local / Q000494:pharmacology*; D002224:Carbanilides / Q000737:chemistry / Q000494:pharmacology*; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D003094:Collagen / Q000502:physiology; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis* / Q000187:drug effects; D004338:Drug Combinations; D004790:Enzyme Induction / Q000187:drug effects; D005109:Extracellular Matrix / Q000502:physiology; D006418:Heme / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D007797:Laminin / Q000502:physiology; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D011509:Proteoglycans / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D014576:Uroporphyrinogen III Synthetase / Q000037:antagonists & inhibitors; D014577:Uroporphyrinogens / Q000096:biosynthesis; D014578:Uroporphyrins / Q000096:biosynthesis
D000891:Anti-Infective Agents, Local; D002224:Carbanilides; D065607:Cytochrome P-450 Enzyme Inhibitors; D004338:Drug Combinations; D007797:Laminin; D011509:Proteoglycans; D014577:Uroporphyrinogens; D014578:Uroporphyrins; C059485:matrigel; D006418:Heme; C034103:uroporphyrin I; C024393:hydroxymethylbilane; D000622:Aminolevulinic Acid; D003094:Collagen; D003577:Cytochrome P-450 Enzyme System; D014576:Uroporphyrinogen III Synthetase; C005055:cloflucarban