Temporal kinetics and concentration–response relationships for induction of CYP1A, CYP2B, and CYP3A in primary cultures of beagle dog hepatocytes

Abstract

Compared to other species, little information is available on the xenobiotic-induced regulation of cytochrome P450 enzymes in the beagle dog. Dogs are widely used in the pharmaceutical industry for many study types, including those that will impact decisions on compound progression. The purpose of this study was (1) to determine the temporal kinetics of drug-induced changes in canine CYP1A, CYP2B, and CYP3A mRNA and enzymatic activity, and (2) to characterize concentration-response relationships for CYP1A2, CYP2B11, and CYP3A12 using primary cultures of canine hepatocytes treated with beta-naphthoflavone (BNF), phenobarbital (PB), and rifampin (RIF), respectively. CYP1A1 and CYP1A2 mRNA exhibited maximal expression (12,700-fold and 206-fold, respectively) after 36 h of treatment with BNF. PB treatment, but not RIF treatment, caused maximal induction of CYP2B11 mRNA (149-fold) after 48 h of treatment. CYP3A12 and CYP3A26 mRNA levels were increased maximally after 72 h of treatment with PB and RIF (CYP3A12, 35-fold and 18-fold, and CYP3A26, 72-fold and 22-fold with PB and RIF treatment, respectively). Concentration-response relationships for BNF induced 7-ethoxyresorufin O-dealkylation (EROD) (EC(50) = 7.8 +/- 4.2 microM), PB induced 7-benzyloxyresorufin O-dealkylation (BROD) (EC(50) = 123 +/- 30 microM), and PB and RIF induced testosterone 6beta-hydroxylation (EC(50) = 132 +/- 28 microM and 0.98 +/- 0.16 microM) resembled the relationship for human CYP induction compared to that of rodent. Interestingly, RIF had no effect on CYP2B11 expression, which represents a species difference overlooked in previous investigations. Overall, the induction of dog CYP1A, CYP2B, and CYP3A exhibits characteristics that are intermediate to those of rodent and human.

Absolute quantification and modulation of cytochrome P450 3A isoforms in cattle liver

“…strate and inducer specificities between CYP3A4 and 3A5, PB induces CYP3A4 but not CYP3A5 gene expression (Matsunaga et al, 2004;Busi and Cresteil, 2005;Pelkonen et al, 2008;Ince et al, 2013). In the present study, all cattle CYP3A isoforms were induced by PB, similar to its effect in the domestic dog, in which PB increased CYP3A12 and 3A26 mRNA levels (Graham et al, 2006). In cattle, the order of magnitude of PB induction was two-to four-times the control value and comparable to the more general CYP3A pattern of up-regulation (Zancanella et al, 2012).…”

“…Among xenobiotics, the non-specific and pleiotropic CYP inducer phenobarbital (PB) has been shown to increase hepatic CYP3A mRNA levels and apoprotein amounts in cattle (Zancanella et al, 2012), and similarly in humans, rodent model species, dogs and pigs (Madan et al, 2003;Anakk et al, 2004;Graham et al, 2006;Magnusson et al, 2006;Puccinelli et al, 2010). In contrast, unexpected results have been observed following the exposure to a known human CYP3A inducer like dexamethasone (Greger and Blum, 2007;Cantiello et al, 2009).…”

A Mechanism-Based Mathematical Model of Aryl Hydrocarbon Receptor-Mediated CYP1A Induction in Rats Using β-Naphthoflavone as a Tool Compound

“…The in vitro EC 50 values for BNF induction of CYP1A activity obtained in hepatocytes of dog (Graham et al, 2006), rat (Madan et al, 1999), and human (unpublished data cited in Graham et al, 2006) were 7.8, 1.5, and 4.2 M, respectively. BNF plasma protein binding in the rat is 96% (Adedoyin et al, 1993).…”

Use of In Vivo Animal Models to Assess Pharmacokinetic Drug-Drug Interactions

“…On the other hand, DDIs caused by CYP induction may be best assessed with both rhesus monkeys (Macaca mulatta) and cynomolgus monkeys in light of the recent extensive studies of DDIs in these species after treatment with standard CYP3A inducers (55,56) and increased mechanistic understanding from those endeavors. Likewise, beagle dogs may have similar potential to estimate CYP induction based on the information collected from a number of studies (57)(58)(59). It has been reported that the induction of dog CYP1A, CYP2B, and CYP3A exhibits characteristics that are intermediate to those of rodent and human (59).…”

“…Likewise, beagle dogs may have similar potential to estimate CYP induction based on the information collected from a number of studies (57)(58)(59). It has been reported that the induction of dog CYP1A, CYP2B, and CYP3A exhibits characteristics that are intermediate to those of rodent and human (59). Kyokawa et al (60) also reported the induction of beagle dog intestinal CYP3A12 by rifampin at a dose (10 mg/kg/day) comparable to the clinical dose for humans (600 mg/man/day).…”