Adult specific expression and induction of cytochrome P450tpr in house flies

✍ Scribed by Jeffrey G. Scott; Padma Sridhar; Nannan Liu

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 681 KB
• Volume: 31
• Category: Article
• ISSN: 0739-4462
• DOI: 10.1002/(sici)1520-6327(1996)31:3<313::aid-arch6>3.0.co;2-y

✦ Synopsis

Cytochrome P450,,, is a xenobiotic metabolizing P450 that is found i n house flies (Musca dornestica). To better understand the regulation of cytochrorne P450,,,, the effects of 21 potential monooxygenase inducers were examined for their ability to induce total cytvchromes P450 and cytochrome P450,,, levels in adult flies. Six compounds caused induction of total cytochromes P450 per mg protein in adult susceptible (CS) house flies: ethanol (1.6-fold), phenobarbital in food (1.5-fold) or water (1.5-fold), naphthalene (1.3-fold), DDT (1.3-fold), xanthotoxin (1.4-foldj, and a-plnene (1.2-fold). Six compounds were found to be inducers of cytochrome P450,,,: piperonyl butoxide in food (1.9fold), phenobarbital in food (1.4-fold) and water (3.4-fold), clofibrate (1.3-fold), xanthotoxin (1 ..?-fold), methohexital (1.3-fold), and isosafrole (1.3-fold). Comparison of our results with house fly P450 6A1 indicates that there are specific inducers for each of these individual P450s as well as compounds that induce both P450s. Total P450s were inducible by PB in CS house fly larvae, but not in LPR larvae. lmrnunoblotting revealed no detectable P450,,, in control or PB-treated larvae in either strain. Thus, although total P4SOs are inducible in the susceptible strain larvae, P450,,, does not appear to be normally present or inducible with PB in larvae of either strain.

Northern blots of phenobarbital (in water) treated CS flies indicated that there was a 4.2-fold increase in the P450,,, (i.e., CYP6D1) mRNA levels over the untreated flies. In the multiresistant LPR strain there was no apparent induction of CYPGD1 mRNA by phenobarbital. Following phenobarbital induction, the level of CYP6D1 rnRNA i n the CS strain was about half of the level in the LPR strain. o 1996 Wiiey-Liss, Inc.