Characterization of microsomal cytochrome P450-dependent monooxygenases in the rat olfactory mucosa.

Nasal administration of a drug ensures therapeutic action by rapid systemic absorption and/or the entry of some molecules into the brain through different routes. Many recent studies have pointed out the presence of xenobiotic-metabolizing enzymes in rat olfactory mucosa (OM). Nevertheless, very little is known about the precise identity of isoforms of cytochrome P450 (P450)-dependent monooxygenases (P450) and their metabolic function in this tissue.

9-cis-Retinoic acid regulation of four UGT isoforms in hepatocytes from rats with various thyroid states.

Purpose: To investigate the influence of thyroid hormone status on the regulation of UGTs expression by 9-cis-retinoic acid in cultured rat primary hepatocytes.

Methods: Hepatocytes from rats with various thyroid states were isolated and treated with 9-cis retinoic acid (1 x 10(-6) M). mRNA was amplified by reverse transcription and polymerase chain reaction (RT-PCR) and quantified by UV light densitometry.

Glucuronidation of odorant molecules in the rat olfactory system: activity, expression and age-linked modifications of UDP-glucuronosyltransferase isoforms, UGT1A6 and UGT2A1, and relation to mitral cell activity.

The aim of the present study was to examine the glucuronidation of a series of odorant molecules by homogenates prepared either with rat olfactory mucosa, olfactory bulb or brain. Most of the odorant molecules tested were efficiently conjugated by olfactory mucosa, whereas olfactory bulb and brain homogenates displayed lower activities and glucuronidated only a few molecules. Important age-related changes in glucuronidation efficiency were observed in olfactory mucosa and bulb.

Vitamin A modulates the effects of thyroid hormone on UDP-glucuronosyltransferase expression and activity in rat liver.

We studied the influence of thyroid hormones and vitamin A status on the regulation of UDP-glucuronosyltransferase (UGT) expression and the glucuronidation of thyroid hormones by UGTs. For this, we used an original model of rats fed with different vitamin A diets and implanted subcutaneously by osmotic minipumps delivering vehicle or thyroid hormones, which permitted the control of plasma thyroid hormone concentrations. The activity and expression of family 1 UGTs are correlated and were significantly modified by both thyroid status and amounts of retinol in the diet.

Induction of cytochrome P450 and/or detoxication enzymes by various extracts of rosemary: description of specific patterns.

The ability of rosemary to modulate cytochrome P450 (CYP) and detoxication enzymes in rat liver was evaluated by comparing the effects of dried leaves and leaf extracts with different chemical compositions: essential oil (EO) containing monoterpenes, a dichloromethane extract (DCME) containing phenolic diterpenes and a water-soluble extract (WSE) containing phenolic compounds such as rosmarinic acid and flavonoids. Chemical analyses were done in order to characterize the composition of extracts. Male Wistar rats received the leaves or extracts of rosemary in their diet at 0.