Induction of Rabbit Lung CYP4A4 Prostaglandin ω-Hydroxylase by Various Steroid Hormones

McCabe, Timothy J.; Roman, Linda J.; Masters, Bettie Sue Siler

doi:10.1006/abbi.2001.2479

Cited by 7 publications

(1 citation statement)

References 26 publications

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“…The other isoform we found in rabbit tongue was CYP4A4. This isoform has been previously reported to be expressed at low basal levels in adult rabbit lungs (McCabe et al, 2001). CYP4A4 is a hormonally induced isoform which metabolizes arachidonic acid to ω-hydroxylated products (Aitken et al, 2001).…”

Section: Discussionmentioning

confidence: 90%

Cytochrome P450 expression and activities in rat, rabbit and bovine tongue

Yang

Medling

Raner

2003

Comparative Biochemistry and Physiology Part C: Toxicology &

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Xenobiotic metabolism in the tongue has received little attention in the literature. In the present study, we report a comparative analysis of constitutive cytochrome P450 (CYP) expression and activities in the tongue. First we compared catalytic activities of rabbit, rat and bovine tongue samples using the probe substrates 4-nitrophenol, 1-phenylethanol, caffeine and 7-ethoxycoumarin. Rabbit tongue samples showed the highest activities for all substrates. We then compared the activities in rat and rabbit tongue with those in the rabbit liver, along with the effects of P450 inhibitors on specific activities. Combined, the activity studies indicate that CYP1A1 is active in rabbit tongue cells, but CYP1A2, CYP3A6 and CYP2E1 are below limits of detection. RT-PCR was also used to compare mRNA levels of 11 different rabbit and six different rat P450 isoforms in the tongue to those in the liver of these two species. Only CYP2E1, CYP1A1 and CYP4A4 were detected at significant levels in the rabbit tongue. None of the six rat isoforms probed were observed in the tongue. Although 4-nitrophenol activity was observed in the rabbit tongue samples, the kinetic parameter K(m) was inconsistent with the involvement of CYP2E1. We suggest that although CYP2E1 is expressed in the tongue, it is rapidly degraded in this organ, and the nitrophenol hydroxylation and caffeine hydroxylation we observe is the result of activity of CYP1A1.

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Section: Discussionmentioning

confidence: 90%