Immunohistochemical study of temporal variations in cytochrome P-450 isozymes in rat testis and their modifications by the inductive effects of cadinenes.
Temporal variations in cytochrome P-450 isozymes of rat testis, PB-P-450 (forms of cytochrome P-450 strongly induced by phenobarbital) and MC-P-448 (forms of cytochrome P-450 strongly induced by 3-methylcholanthrene), were investigated immunohistochemically by the avidin-biotin-complex method using specific antibodies against PB-P-450 and MC-P-448 isozymes. Immunoreactivity to both PB-P-450 and MC-P-448 isozymes was observed in Leydig cells. The number of PB-P-450 positive Leydig cells was found to undergo significant time-of-day variation with a peak time of 0000 hours (light phase from 0800 to 2000 hours). Injection of cadinenes (300 mg/kg per day intraperitoneally at 48 and 96 h before sacrifice) induced PB-P-450 isozyme but did not induce MC-P-448 isozyme. The induction of PB-P-450 isozyme by cadinenes was time dependent, and the early dark phase (2000 and 0000 hours) was most sensitive. These results suggest that temporal variation of cytochrome P-450 isozymes is one of the important physiological variations in detoxification and activation of various xenobiotics and chemicals in the testis.
Kobayashi
Y
Y
Department of Clinical Pathology, Saitama Institute of Cancer, Japan.
Motohashi
Y
Y
Miyazaki
Y
Y
Yatagai
M
M
Takano
T
T
D000818:Animals; D002940:Circadian Rhythm / Q000187:drug effects; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004790:Enzyme Induction / Q000187:drug effects; D007527:Isoenzymes / Q000378:metabolism; D008297:Male; D010936:Plant Extracts / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013737:Testis / Q000187:drug effects / Q000201:enzymology*
D007527:Isoenzymes; D010936:Plant Extracts; D003577:Cytochrome P-450 Enzyme System