Promjene citokroma P450 jetre i mozga nakon višekratne primjene kokaina, samog ili u kombinaciji s nifedipinom

The objective of this study was to evaluate possible changes caused by multiple cocaine administration, alone and in combination with 1,4-dihydropiridine calcium channel blocker nifedipine, on cytochrome P450 levels both in the brain and liver. The experiment was done on male Wistar rats divided in four groups: control, treated with nifedipine (5 mg kg-1 i.p. for five days), treated with cocaine (15 mg kg-1 i.p. for five days), and treated with nifedipine and 30 minutes later with cocaine (also for five days). Total cytochrome P450 was measured spectrometrically in liver and brain microsomes. Multiple administration of cocaine alone and in combination with nifedipine did not change the brain P450 significantly. In the liver, nifedipine significantly increased P450 by 28 % vs. control. In contrast, cocaine significantly decreased P450 by 17 % vs. control. In animals treated with nifedipine and cocaine, cytochrome P450 increased 11 % (p<0.01) vs. control, decreased 12.5 % (p<0.001) vs. nifedipine group and increased 34 % (p<0.0001) vs. cocaine group. These results suggest that the cocaine and nifedipine interact at the metabolic level.Cilj je ovog istraživanja bio ocijeniti moguće promjene uzrokovane višestrukom primjenom kokaina kao jedinog agensa odnosno u kombinaciji s nifedipinom, 1,4-dihidropiridinskim blokatorom kalcijevih kanala, na razine citokroma P450 u mozgu i jetri štakora. Životinje (mužjaci Wistar štakora) podijeljene su u četiri skupine: kontrolnu skupinu, skupinu koja je primala nifedipin (5 mg kg-1 ip. pet dana), skupinu koja je primala kokain (15 mg kg-1 ip. pet dana) i skupinu koja je primala nifedipin te pola sata kasnije kokain (također pet dana). Ukupna količina citokroma P450 mjerena je spektrofotometrijski u mikrosomima jetre i mozga. Višestruka primjena samo kokaina odnosno u kombinaciji s nifedipinom nije značajno promijenila razine citokroma P450 u mozgu. U jetri je međutim nifedipin u odnosu na kontrolnu skupinu uzrokovao povišenje razina P450, za statistički značajnih 28 %. Kokain je uzrokovao statistički značajan pad razine P450 za 17 % u odnosu na kontrolnu skupinu. U životinja koje su primale kombinaciju nifedipina i kokaina razina citokroma P450 narasla je za 11 % (p<0.01) u odnosu na kontrolu, bila je 12.5 % (p<0.001) niža u odnosu na skupinu koja je primala nifedipin te viša za 34 % (p<0.0001) u odnosu na skupinu koja je primala samo kokain. Rezultati ovog istraživanja upućuju na interakcije ovih spojeva koje se odvijaju na razini metabolizm

Forty years literature review of primary lung lymphoma

There are several unresolved issues through out the literature regarding the entity of primary lung lymphoma. Extensive literature review of this uncommon pathology is carried out

Differential effects of diabetes on CYP2E1 and CYP2B4 proteins and associated drug metabolizing enzyme activities in rabbit liver

The effects of diabetes on cytochrome P450 (CYP)-dependent drug metabolizing enzymes are yet to be clarified. The most widely used animals in these studies have been rats, and information on the effects of diabetes on rabbit liver drug metabolizing enzymes have been unavailable until now. In this study, for the first time, a significant induction of liver CYP2E1 is demonstrated via immunoblot analysis in alloxan-induced rabbits. The CYP2E1 content of diabetic microsomes was highly correlated with the activities of liver aniline 4-hydroxylase (r=0.82, p < 0.05), and p-nitrophenol hydroxylase (r=0.86, p < 0.01), and diabetes increased the activities of the enzymes associated with CYP2E1. The activities of aniline 4-hydroxylase and p-nitrophenol hydroxylase were significantly increased by 1.7 and 1.8-fold, respectively compared to those of control rabbits. In marked contrast, diabetes had no effect on the protein levels of CYP2B4 as determined by immunoblotting and on benzphetamine N-demethylase activity, which is known to be specifically metabolized by CYP2B4 in rabbit liver. The present study demonstrates that diabetes increases the activities of CYP2E1 and associated enzymes but does not change the activity levels of CYP2B4 and associated enzymes in diabetic rabbits. These findings are in contrast to those of mice, hamsters and rats, and that suggest the presence of species-dependent responses of CYP-dependent drug metabolizing enzymes to diabetes

STABILITY AND STORAGE-CONDITIONS OF NADH-CYTOCHROME B5 REDUCTASE CROSS-LINKED INTO GELATIN BY CHROMIUM(III) ACETATE

NADH-cytochrome b5 reductase was isolated and partially purified from rabbit liver microsomes. It was immobilized into gelatin by chemical cross-linking. Chromium (III) acetate was used as cross-linker. The effects of pH and temperature on the immobilized cytochrome b5 reductase were investigated. The reusability and storage stability of immobilized enzyme were also tested. Immobilized NADH-cytochrome b5 reductase activities were found to be stable for at least 72 d and 24 uses. The storage stability of NADH-cytochrome b5 reductase was improved with immobilization at 25 degrees C

human hepatocarcinoma cells

Humans are exposed to acrylamide in their diet and cigarette smoke. Acrylamide is metabolized into glycidamide by CYP2E1. However, very few studies regarding the effects of acrylamide on cytochrome P450 and Glutathione S-Transferase (GST) isozymes have been pursued. The aim of this study is to elucidate the effects of acrylamide on cytochrome P450 and GST isozymes in HepG2 cell line. Treatment with 1.25 and 2.5 mM acrylamide caused 9.5- and 3.7-fold increases and 4.0- and 3.3-fold increases in CYP1A-associated ethoxyresorufin O-deethylase (EROD) and methoxyresorufin O-demethylase (MROD) activities, respectively. These increases were consistent with increases in mRNA and protein levels of these isozymes. Similarly, CYP2E1-associated aniline 4-hydroxylase (ANH) activity, protein levels, and mRNA levels increased 2.1- and 2.6-fold, 2.4- and 3.2-fold, and 1.4- and 1.9-fold following 1.25 and 2.5 mM acrylamide treatments, respectively. In addition, GST-mu activity was increased 2.4- and 5.1-fold by acrylamide. Moreover, GST-mu mRNA and protein levels increased twofold as a result of acrylamide treatment. In contrast, GST-pi protein and mRNA levels decreased significantly. In conclusion, human cell exposure to acrylamide causes an increase in the levels of carcinogenicity and toxicity and a disturbance in drug metabolism, possibly due to complex effects on P450 and GST isozymes

Characterization of aldrin epoxidation in flathead mullet (Mugil cephalus) liver microsomes: Involvement of CYP3A

Toxic organochlorine pesticides, aldrin and its metabolite dieldrin, have been reported to contaminate the aquatic environment highly. In the present study, epoxidation reaction of aldrin to dieldrin was studied in mullet liver microsomes and contribution of cytochrome P450 isozyme(s) was determined by using specific cytochrome P450 inhibitors and substrate. Flathead mullet samples (Mugil cephalus) were caught from the West Black Sea Region of Turkey. Fish liver microsomes were prepared by differential centrifugation. Epoxidation of aldrin to dieldrin was determined by measuring the amount of dieldrin produced using gas chromatography and electron capture detector. Aldrin epoxidation was linear with time up to 60 min and with protein concentration up to 10 mg/mL. Maximal fish liver aldrin epoxidase activity was observed at pH 7.6. Aldrin epoxidase exhibited monophasic kinetics with apparent Km value of 140 μM for aldrin. The enzyme activity was inhibited approximately by 9% and 16% by methanol and DMSO, respectively. On the other hand, aldrin epoxidation was enhanced by about 113% with 2% ethanol in the incubation medium. Ketoconazole (CYP3A inhibitor), potentially inhibited the metabolism of aldrin, tolbutamide (CYP2C substrate), and alpha-naphthoflavone (CYP1A inhibitor) did not show inhibition. The results of this study strongly suggest that CYP3A is the cytochrome P450 isozyme involved in aldrin epoxidation in mullet liver microsomes whereas CYP2C and CYP1A are not involved