Preliminary Study On Microsomal Cytochrome P450 Enzymes In Pigs

The drug interactions at microsome level are studied more and more recently, but research on medicines metabolizability in food animals are seldom reported. Microsomal cytochrome P450 enzymes in pigs were studied in this paper. The method was used to determine the CYP450 in pigs, the effects of several clinical medicines and flunixin meglumine on CYP450 in pigs were evaluated. The details as follow:Pig liver microsome protein content and P450 enzymes activities were studied by biochemical and ultraviolet spectrophotometry method. The fresh pig liver samples were refined, and liver microsome was distilled by different velocity centrifugation. The Bradford method was used to measure the concentration of protein in liver microsome, and activities of cytochrome P450 enzymes were determined by the spectrophotometer method. Value of liver microsome protein content, CYP450 content, CYPb5 content, NADPH-CytochromeC reductase activity, aminopyrine-N-demethylase activity, erythromycin-N-demethylase activity and aniline-4-hydroxylase activity were measured in different sex pigs within one month to eight month old. Result suggested that protein concentration in hepatic microsome of pigs with age from one month to eight month was 6.646 ± 0.457-13.596 ± 1.077 mg/ml, content of cytochrome P450 was 0.270 ± 0.044-0.587 ± 0.043 nmol/mg protein, content of cytochrome b5 was 0.105 ± 0.019-0.251 ± 0.018 nmol/mg protein, the activity of NADPH-CytochromeC reductase was 1.632 ± 0.255-3.043 ±0.229 nmol/min/mg protein, the activity of AND was 0.625 ± 0.071-2.990 ± 0.144 nmol/min/mg protein, the activity of ERND was 0.562 ± 0.095-2.540 ± 0.177 nmol/min/mg protein, and the activity of AH was 0.090 ± 0.016-0.231 ± 0.021 nmol/min/mg protein. The established method for determining contents and activities of hepatic microsomal cytochrome P450s in pigs was sensitive, simple, credibility with good reproducibility. The protein content of the pig liver microsome and P450 enzymes, growing along with the ages, was increasing and strengthened. And the liver microsome protein content, CYP450 content and erythromycin-N-demethylase activity appear some gender differences.Effects of several clinical medicines on cytochrome P450 enzymes in pigs were studied. Erythromycin, ciprofloxacin, dexamethasone and ethanol were given to pigs by intramuscular injection at a single dose of 5 times of the normal dosage continuously for 10 days, respectively. Liver microsome was distilled by different velocity centrifugation. The...