Effect of isotretinoin on CYP2D6 and CYP3A activity in patients with severe acne.

Aims: Previously, retinoids have decreased CYP2D6 mRNA expression in vitro and induced CYP3A4 in vitro and in vivo. This study aimed to determine whether isotretinoin administration changes CYP2D6 and CYP3A activities in patients with severe acne.

Methods: Thirty-three patients (22 females and 11 males, 23.

Impact of Pregnancy and Vitamin A Supplementation on CYP2D6 Activity.

The mechanism of cytochrome P450 2D6 (CYP2D6) induction during pregnancy has not been evaluated in humans. This study assessed the changes in CYP2D6 and CYP3A activities during pregnancy and postpartum, and the effect of vitamin A administration on CYP2D6 activity. Forty-seven pregnant CYP2D6 extensive metabolizers (with CYP2D6 activity scores of 1 to 2) received dextromethorphan (DM) 30 mg orally as a single dose during 3 study windows (at 25 to 28 weeks of gestation, study day 1; at 28 to 32 weeks of gestation, study day 2; and at ≥3 months postpartum, study day 3).

Plasma Retinoid Concentrations Are Altered in Pregnant Women.

Vitamin A is vital to maternal-fetal health and pregnancy outcomes. However, little is known about pregnancy associated changes in maternal vitamin A homeostasis and concentrations of circulating retinol metabolites. The goal of this study was to characterize retinoid concentrations in healthy women ( = 23) during two stages of pregnancy (25-28 weeks gestation and 28-32 weeks gestation) as compared to ≥3 months postpartum.

Evidence of depot-specific regulation of all-trans-retinoic acid biosynthesis in human adipose tissue.

The prevalence of obesity continues to rise, underscoring the need to better understand the pathways mediating adipose tissue (AT) expansion. All-trans-retinoic acid (atRA), a bioactive vitamin A metabolite, regulates adipogenesis and energy metabolism, and, in rodent studies, aberrant vitamin A metabolism appears a key facet of metabolic dysregulation. The relevance of these findings to human disease is unknown, as are the specific enzymes implicated in vitamin A metabolism within human AT.

The retinoic acid hydroxylase Cyp26a1 has minor effects on postnatal vitamin A homeostasis, but is required for exogenous RA clearance.

The all--retinoic acid (RA) hydroxylase Cyp26a1 is essential for embryonic development and may play a key role in regulating RA clearance also in adults. We hypothesized that loss of Cyp26a1 activity via inducible knockout in juvenile or adult mice would result in decreased RA clearance and increased tissue RA concentrations and RA-related adverse effects. To test these hypotheses, Cyp26a1 was knocked out in juvenile and adult male and female floxed mice using standard Cre-Lox technology and tamoxifen injections.

Economic instruments for obesity prevention: results of a scoping review and modified Delphi survey.

Background: Comprehensive, multi-level approaches are required to address obesity. One important target for intervention is the economic domain. The purpose of this study was to synthesize existing evidence regarding the impact of economic policies targeting obesity and its causal behaviours (diet, physical activity), and to make specific recommendations for the Canadian context.