This article is available online at http://dmd.aspetjournals.org ABSTRACT:UDP-Glucuronosyltransferases (UGTs) are phase II biotransformation enzymes that glucuronidate numerous endobiotic and xenobiotic substrates. Glucuronidation increases the water solubility of the substrate and facilitates renal and biliary excretion of the resulting glucuronide conjugate. UGTs have been divided into two gene families, UGT1 and UGT2. Tissue distribution of UGTs has not been thoroughly examined, and such data could provide insight into the importance of individual UGT isoforms in specific tissues and to the pharmacokinetics and target organ toxicity of UGT substrates. Therefore, the aim of this study was to determine mRNA levels of rat UGT1 and UGT2 family members in liver, kidney, lung, stomach, duodenum, jejunum, ileum, large intestine, cerebellum, and cerebral cortex, as well as nasal epithelium for UGT2A1. Tissue levels of UGT mRNA were detected using branched DNA signal amplification analysis. Three UGT isoforms, UGT1A1, UGT1A6, and UGT2B12, were detected in many tissues, whereas distribution of other UGT isoforms was more tissue-specific. For example, UGT2A1 was detected predominantly in nasal epithelium. Additionally, UGT1A5, UGT2B1, UGT2B2, UGT2B3, and UGT2B6 were detected primarily in liver. Furthermore, detection of UGT1A2, UGT1A3, UGT1A7, and UGT2B8 was somewhat specific to gastrointestinal (GI) tract. However, not all of these UGTs were detected in all portions of the GI tract. UGT1A8 was unique in that it was barely detectable in any of the tissues examined. In conclusion, some UGT isoforms were expressed in multiple tissues, whereas other UGT isoforms were predominantly expressed in a certain tissue such as nasal epithelium, liver, or GI tract.

Excessive fluid intake can substantially dilute urinary drug concentrations and result in false-negative reports for drug users. Methods for correction ("normalization") of drug/metabolite concentrations in urine have been utilized by anti-doping laboratories, pain monitoring programs, and in environmental monitoring programs to compensate for excessive hydration, but such procedures have not been used routinely in workplace, legal, and treatment settings. We evaluated two drug normalization procedures based on specific gravity and creatinine. These corrections were applied to urine specimens collected from three distinct groups (pain patients, heroin users, and marijuana/ cocaine users). Each group was unique in characteristics, study design, and dosing conditions. The results of the two normalization procedures were highly correlated (r=0.94; range, 0.78-0.99). Increases in percent positives by specific gravity and creatinine normalization were small (0.3% and -1.0%, respectively) for heroin users (normally hydrated subjects), modest (4.2-9.8%) for pain patients (unknown hydration state), and substantial (2- to 38-fold increases) for marijuana/cocaine users (excessively hydrated subjects). Despite some limitations, these normalization procedures provide alternative means of dealing with highly dilute, dilute, and concentrated urine specimens. Drug/metabolite concentration normalization by these procedures is recommended for urine testing programs, especially as a means of coping with dilute specimens.

ABSTRACT:Microsomal enzyme inducers (MEIs) up-regulate phase I biotransformation enzymes, most notably cytochromes P450. Transcriptional up-regulation by MEIs occurs through at least three nuclear receptor mechanisms: constitutive androstane receptor (CAR; CYP2B inducers), pregnane X receptor (PXR; CYP3A inducers), and peroxisome proliferator-activated receptor ␣ (PPAR␣; CYP4A inducers). Other mechanisms include transcription factors aryl hydrocarbon receptor (AhR; CYP1A inducers), and nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2; NADPH-quinone oxidoreductase inducers). UDP-glucuronosyltransferases (UGTs) are phase II biotransformation enzymes that are predominantly expressed in liver and intestine. MEIs increase UGT activity; however, transcriptional regulation of individual UGT isoforms is not completely understood. The purpose of this study was to examine inducibility of individual UGT isoforms and potential mechanisms of transcriptional regulation in rat liver and duodenum. UGT mRNA levels were assessed in liver and duodenum of rats treated with MEIs that activate various transcriptional pathways. All four CAR activators induced UGT2B1 in liver, but not duodenum. UGT1A1, 1A5, 1A6, and 2B12 were induced by at least two CAR activators in liver only. Two PXR ligands induced UGT1A2, but only in duodenum. Two PPAR␣ ligands induced UGT1A1 and 1A3 in liver only. AhR ligands induced UGT1A6 and 1A7 in liver, but not duodenum. Nrf2 activators increased UGT2B3 and 2B12 in both liver and duodenum, and UGT1A6, 1A7, and 2B1 in liver only. In summary, only UGT1A2 and 1A8 were not inducible in liver by MEIs. MEIs differentially regulate hepatic expression of individual UGT isoforms, although no one transcriptional pathway dominated. In duodenum, MEIs had minimal effects on UGT expression.

A number of synthetic cannabinoids such as JWH-018 and JWH-073 have been incorporated into "spice" products. Despite having labels warning against human consumption, the products are smoked for their cannabinoid-like effects and the extent of their use by athletes has not been adequately described. Urine samples collected from 5,956 athletes were analyzed by high-performance liquid chromatography-tandem mass spectrometry for the presence of JWH-018, JWH-073, and their metabolites. Metabolites of JWH-018 and/or JWH-073 were detected in 4.5% of the samples. Metabolites of JWH-018 and JWH-073, only JWH-018, and only JWH-073 were detected in 50%, 49%, and approximately 1% of positive samples, respectively. In total, JWH-018 metabolites were detected in 99% (50% + 49%) and JWH-073 metabolites were detected in approximately 50% (49% + 1%) of the positive samples. Parent JWH-018, JWH-018-2-OH-indole, and JWH-018-4-OH-indole were not detected in any of the samples. All samples in which JWH-073 metabolites were detected contained JWH-073-N-butanoic acid. Parent JWH-073 and its N-(4-OH-butyl), 4-OH-indole, 5-OH-indole, and 7-OH-indole metabolites were not detected. Given the number of synthetic cannabinoids that have been synthesized, their limited regulation, and the prevalence of JWH-018 and JWH-073 metabolites detected in the athletes, these compounds should remain a priority for anti-doping programs.

Because of their perceived and reported effects on self-image, muscle development, performance, and similar factors, anabolic-androgenic steroids (AAS) and their precursors are among the most abused substances by professional, amateur, and recreational athletes. However, AAS abuse is not limited to athletes, but is also prevalent in the workplace, especially those professions in which image, strength, and endurance are coveted attributes. The detection of many steroids in biological specimens is analogous to the detection of an abused drug such as cocaine. Identification of the parent drug or its characteristic metabolite(s) in a donor's sample with a drug screening technique and confirmation of the drug/metabolite with a suitable alternative technology provides evidence of use. These analyses and subsequent interpretive scenarios become far more complex when the ingested AAS is an endogenous compound such as dehydroepiandrosterone (DHEA), androstenedione (Adione), or dihydrotestosterone (DHT). These compounds and their metabolites are present in specimens such as urine as a course of our natural endocrine function. Therefore, it becomes much more challenging for the laboratory to establish testing and interpretative paradigms that can distinguish "normal" urinary profiles of these steroids and their metabolites from profiles indicative of exogenous use. Distinguishing "normal" from "abnormal" urine profiles is particularly challenging during screening when literally tens of steroids and their metabolites may be tested simultaneously in a single chromatographic analysis. The purpose of this paper is to review the relevant literature about DHEA, Adione, and DHT administration, detection, and interpretation specifically as it relates to changes in the urinary AAS profile that may be identified during the routine laboratory screening of donor urine specimens.