Age- and gender-related trends in the expression of glutathione S-transferases in human nasal mucosa

Characterization of rat glutathione transferases in olfactory epithelium and mucus

The olfactory epithelium is continuously exposed to exogenous chemicals, including odorants. During the past decade, the enzymes surrounding the olfactory receptors have been shown to make an important contribution to the process of olfaction. Mammalian xenobiotic metabolizing enzymes, such as cytochrome P450, esterases and glutathione transferases (GSTs), have been shown to participate in odorant clearance from the olfactory receptor environment, consequently contributing to the maintenance of sensitivity toward odorants. GSTs have previously been shown to be involved in numerous physiological processes, including detoxification, steroid hormone biosynthesis, and amino acid catabolism. These enzymes ensure either the capture or the glutathione conjugation of a large number of ligands. Using a multi-technique approach (proteomic, immunocytochemistry and activity assays), our results indicate that GSTs play an important role in the rat olfactory process. First, proteomic analysis demonstrated the presence of different putative odorant metabolizing enzymes, including different GSTs, in the rat nasal mucus. Second, GST expression was investigated in situ in rat olfactory tissues using immunohistochemical methods. Third, the activity of the main GST (GSTM2) odorant was studied with in vitro experiments. Recombinant GSTM2 was used to screen a set of odorants and characterize the nature of its interaction with the odorants. Our results support a significant role of GSTs in the modulation of odorant availability for receptors in the peripheral olfactory process.

The human olfactory cleft mucus proteome and its age-related changes

Age-related decreases in olfactory sensitivity are often accompanied by a decrease in the quality of life. However, the molecular mechanisms underlying these changes are not well described. Inhaled substances including odorants are detected by sensory neurons in the olfactory cleft covered with a layer of mucus. This olfactory mucus is the first molecular machinery responsible for tissue protection and for detection of environmental odorants. Yet, little is known about the molecular identities of the actors because of the lack of information on the mucus proteome and its age-related changes. Here, we sampled human mucus from different nasal locations and from young and elderly subjects. The composition of the mucus was extensively analyzed by shotgun proteomic analysis for a vast array of proteins. We also explored correlations between the levels of each mucus proteins with the olfactory sensitivity of subjects. This analysis revealed previously unrecognized proteins with potentially important functions in olfaction. Taken together, this report describes the most comprehensive catalogue of the nasal mucus proteins to date, their positional and age-related differences, and candidate proteins associated with olfaction. This catalogue will provide fundamental information useful for future studies, such as identification of olfactory auxiliary proteins, causes of age-related declines in olfaction, and biomarkers for neurodegenerative disorders.

Age-Related Deficits in Taste and Smell

Disturbances in both the ability to smell and to taste are common in older persons. Such disturbances influence nutrition, safety, quality of life, and psychological and physical health. The anatomic and physiologic causes of age-related disturbances are multiple and interacting, and depend on genetic and environmental factors. Frank losses of function, distortions, and hallucinations are common. Most distortions resolve over time, although this can take months or even years. Olfactory dysfunction occurs during the earliest stages of several neurologic disorders, most notably Alzheimer's disease and Parkinson's disease, likely heralding the onset of the underlying pathologies.

Na+/K+-ATPase, acetylcholinesterase and glutathione S-transferase activities as new markers of postmortem interval in Swiss mice

Determining precisely the postmortem interval (PMI) is a key parameter for forensic researches, given that various physical, biochemical and metabolic changes begin to occur in the body after death. In the present study, the Na⁺/K⁺-ATPase, glutathione S-transferase (GST) and acetylcholinesterase (AChE) activities were evaluated. For this, male adult Swiss mice were killed by isoflurane inhalation anesthesia and divided into four groups according to time of death (0, 6, 24 and 48 h). The brain, liver, kidney and skeletal muscle tissues were removed. Our results revealed that at the time of 6 h, there was a decrease on Na⁺/K⁺-ATPase and GST activities in the brain and liver tissues, respectively. In addition, at this time point, an increase on renal GST activity was verified. At the time of 24 h, an increase on the cerebral AChE and renal GST activities was observed, while the cerebral Na⁺/K⁺-ATPase activity was decreased. Forty-eight hours after death, cerebral Na⁺/K⁺-ATPase and renal GST activities remained decreased and increased, respectively. In addition, no alteration was observed on the GST activity in the skeletal muscle and brain (in PMIs evaluated). The present study revealed that the brain and kidney (at the times of 24 and 48 h) were the tissues that suffered the most changes in almost all the enzymes evaluated. Our results demonstrated that enzyme activity assessments are reliable, easy-to-perform and low-cost determinations, and could be promising postmortem markers.

Sex-Dependent effects of developmental arsenic exposure on methylation capacity and methylation regulation of the glucocorticoid receptor system in the embryonic mouse brain

Previously we have shown that prenatal moderate arsenic exposure (50 ppb) disrupts glucocorticoid receptor (GR) programming and that these changes continue into adolescence in males. However, it was not clear what the molecular mechanisms were promoting these GR programming changes or if these changes occurred in arsenic-exposed females. In the present studies, we assessed the effects of arsenic on protein and mRNA of the glucocorticoid receptor (GR) and 11β-hydroxysteroid dehydrogenase (Hsd) isozymes and compared the levels of methylation within the promoters of the Nr3c1 and Hsd11b1 genes in female fetal brain at embryonic days (E) 14 and 18. Prenatal arsenate exposure produced sex specific effects on the glucocorticoid system. Compared to males, females were resistant to arsenic induced changes in GR, 11β-Hsd-1 and 11β-Hsd-2 protein levels despite observed elevations in Nr3c1 and Hsd11b2 mRNA. This sex-specific effect was not due to differences in the methylation of the GR promoter as methylation of the Nr3c1 gene was either unchanged (region containing the egr-1 binding site) or similarly reduced (region containing the SP-1 transcription factor binding site) in both males and females exposed to arsenic. Arsenic did produce sex and age-specific changes in the methylation of Hsd11b1 gene, producing increased methylation in females at E14 and decreased methylation at E18.These changes were not attributed to changes in DNMT levels. Since arsenate metabolism could interfere with the generation of methyl donor groups, we assessed glutathione (GSH), S-adenosylmethionine (SAM) and As 3 methyltransferase (As3MT). Exposed males and females had similar levels of As3MT and SAM; however, females had higher levels of GSH/GSSH. It is possible that this greater anti-oxidative capacity within the females provides protection against low to moderate arsenate. Our data suggest that the GR signaling system in female offspring was not as affected by prenatal arsenic and predicts that female arsenic-exposed mice should have normal GR feedback regulation.

Development of normative data for the Brazilian adaptation of the University of Pennsylvania Smell Identification Test

It is well established that olfactory dysfunction has significant implications for safety, nutrition, and quality of life. The more reliable standardized tests of olfactory function, such as the University of Pennsylvania Smell Identification Test (UPSIT), assess odor identification ability. Unfortunately, cultural factors can influence such tests, as a number of odors are not universally recognized. In this study, a Portuguese language version of the UPSIT was administered to an age- and sex-stratified prospective sample of 1820 Brazilian subjects. Normative data were developed for a subset of 1578 subjects who reported having no difficulties smelling or tasting. Individuals with a history of head trauma or, in the case of those over the age of 64 years, Mini-Mental State Examination Scores <24, were excluded from analysis. As in other populations, the test scores were significantly influenced by age and sex. The median overall difference between the North American and Brazilian UPSIT scores was 2.2 points for men and 0.8 points for women, although subtle age-related differences were also apparent. This research represents that largest clinical study of olfaction ever performed in South America. Correction factors based upon age and sex are provided to allow for direct comparisons of Brazilian test scores to those based upon North American norms.

The influences of age on olfaction: a review

Decreased olfactory function is very common in the older population, being present in over half of those between the ages of 65 and 80 years and in over three quarters of those over the age of 80 years. Such dysfunction significantly influences physical well-being and quality of life, nutrition, the enjoyment of food, as well as everyday safety. Indeed a disproportionate number of the elderly die in accident gas poisonings each year. As described in this review, multiple factors contribute to such age-related loss, including altered nasal engorgement, increased propensity for nasal disease, cumulative damage to the olfactory epithelium from viral and other environmental insults, decrements in mucosal metabolizing enzymes, ossification of cribriform plate foramina, loss of selectivity of receptor cells to odorants, changes in neurotransmitter and neuromodulator systems, and neuronal expression of aberrant proteins associated with neurodegenerative disease. It is now well established that decreased smell loss can be an early sign of such neurodegenerative diseases as Alzheimer's disease and sporadic Parkinson's disease. In this review we provide an overview of the anatomy and physiology of the aging olfactory system, how this system is clinically evaluated, and the multiple pathophysiological factors that are associated with its dysfunction.

Development of a physiologically based pharmacokinetic (PBPK) model for methyl iodide in rats, rabbits, and humans

Methyl iodide (MeI) has been proposed as an alternative to methyl bromide as a pre-plant soil fumigant that does not deplete stratospheric ozone. In inhalation toxicity studies performed in animals as part of the registration process, three effects have been identified that warrant consideration in developing toxicity reference values for human risk assessment: nasal lesions (rat), acute neurotoxicity (rat), and fetal loss (rabbit). Uncertainties in the risk assessment can be reduced by using an internal measure of target tissue dose that is linked to the likely mode of action (MOA) for the toxicity of MeI, rather than the external exposure concentration. Physiologically based pharmacokinetic (PBPK) models have been developed for MeI and used to reduce uncertainties in the risk assessment extrapolations (e.g. interspecies, high to low dose, exposure scenario). PBPK model-derived human equivalent concentrations comparable to the animal study NOAELs (no observed adverse effect levels) for the endpoints of interest were developed for a 1-day, 24-hr exposure of bystanders or 8 hr/day exposure of workers. Variability analyses of the PBPK models support application of uncertainty factors (UF) of approximately 2 for intrahuman pharmacokinetic variability for the nasal effects and acute neurotoxicity.

Cellular and molecular characterization of oxidative stress in olfactory epithelium of Harlequin mutant mouse

Oxidative stress in the olfactory system is a major factor associated with age-related olfactory impairment, although the mechanisms by which this occurs are not completely understood. The Harlequin mutant mouse (Hq/Y), which carries an X-linked recessive mutation in the Aifm1 gene, is a model of progressive oxidative stress-induced neurodegeneration in the cerebellum and retina. To determine whether the Hq/Y mutant mouse is a suitable model of oxidative stress-associated olfactory aging, we investigated cellular and molecular changes in the olfactory epithelium (OE) and olfactory bulb (OB) of 6-month-old male Hq/Y mice compared to those in sex-matched littermate controls (+/Y) and in age- and sex-matched C57BL/6 mice. Immunoreactivity for apoptosis-inducing factor, the protein product of Aifm1, was localized in mature olfactory sensory neurons (mOSNs) in +/Y mice but was rarely detected in Hq/Y mice. Hq/Y mice also exhibited increased lipofuscin autofluorescence and increased immunoreactivity for an oxidative DNA/RNA damage marker in mOSNs and in mitral/tufted cells in the OB and an increased number of cleaved caspase-3 immunoreactive apoptotic cells in the OE. Microarray analysis demonstrated that Aifm1 expression was down-regulated by 80% in the OE of Hq/Y mice compared to that in +/Y mice. Most significantly, regulated genes were classified into functional categories of cell signaling/apoptosis/cell cycle, oxidative stress/aging, and cytoskeleton/extracellular matrix/transport-associated. Analysis with EASE software indicated that the functional categories significantly overrepresented in Hq/Y mice included up-regulated mitochondrial genes and down-regulated cytoskeletal organization- and neurogenesis-related genes. Our results strongly support the Hq/Y mutant mouse being a novel model for mechanistic studies of oxidative stress-associated olfactory aging.

Oxidative stress in the aging murine olfactory bulb: redox proteomics and cellular localization

A recent proteomics analysis from our laboratory demonstrated that several oxidative stress response proteins showed significant changes in steady-state levels in olfactory bulbs (OBs) of 20- vs. 1.5-month-old mice. Oxidative stress may result in protein oxidation. In this study, we investigated two forms of protein oxidative modification in murine OBs: carbonylation and nitration. Redox proteomics with two-dimensional gel electrophoresis, Western blotting, protein digestion, and mass spectrometry was used to quantify total and specific protein carbonylation and to identify differentially carbonylated proteins and determine the carbonylation status of previously identified proteins in OBs of 1.5- and 20-month-old mice. Immunohistochemistry was used to demonstrate the relative intensity and localization of protein nitration in OBs of 1.5-, 6-, and 20-month-old mice. Total protein carbonylation was significantly greater in OBs of 20- vs. 1.5-month-old mice. Aldolase 1 (ALDO1) showed significantly more carbonylation in OBs from 20- vs. 1.5-month-old mice; heat shock protein 9A and dihydropyrimidinase-like 2 showed significantly less. Several previously investigated proteins were also carbonylated, including ferritin heavy chain (FTH). Nitration, identified by 3-nitrotyrosine immunoreactivity, was least abundant at 1.5 months, intermediate at 6 months, and greatest at 20 months and was localized primarily in blood vessels. Proteins that were specific targets of oxidation were also localized: ALDO1 in astrocytes of the granule cell layer and FTH in mitral/tufted cells. These results indicate that specific carbonylated proteins, including those in astrocytes and mitral/tufted neurons, and nitrated proteins in the vasculature are molecular substrates of age-related olfactory dysfunction.

Identification of human olfactory cleft mucus proteins using proteomic analysis

In humans, the olfactory epithelium is located in two narrow passages, the olfactory clefts, at the upper part of the nasal cavities. The olfactory epithelium is covered by a mucus layer which is essential for the function of the olfactory neurons that are directly connected with the brain through the cribriform plate. This anatomical weakness of the brain protection may be the source of infection. Little is known about the composition of this mucus in humans. Previous proteomic analyses have been performed on washes of the entire nasal cavities and therefore might better correspond to the mucus over the respiratory epithelium than to the mucus covering the olfactory epithelium. In the present study, we sampled the olfactory mucus directly from the clefts of 16 healthy adult volunteers, and 83 proteins were identified in the samples using two-dimensional gel electrophoresis, MALDI-TOF, RPLC, and Edman sequencing. Forty-three proteins were not previously observed either in nasal mucus sampled through washings, saliva, tear, or cerebrospinal fluid. In Accordance with the data in the protein databases, the most abundant proteins are secreted, whereas some others correspond to intracellular proteins covering a large range of functions: anti-inflammatory, antimicrobial, protease inhibition, antioxidant, transport, transcription, transduction, cytoskeletal, regulation, binding, and metabolism of odorant molecules. This study clearly demonstrates the complexity of the mucus covering the human olfactory epithelium, which might comprise potential markers for characterizing pathophysiological states.

Polymorphism at the glutathione S-transferase P1 locus in Korean patients with perennial allergic rhinitis

BACKGROUND

Oxidative stresses, which induce the reactive oxygen species (ROS), can cause airway inflammation. The glutathione S-transferases (GSTs) protect cells against the effects of ROS. GSTP1 polymorphism may have some effect on allergic rhinitis. Therefore, we have compared the effects of GSTP1 polymorphisms on the perennial allergic rhinitis in Koreans.

METHODS

Patients with perennial allergies (149 patients) were selected. The control group included 156 healthy people. Genotypes were evaluated via polymerase chain reaction and restriction fragment length polymorphism, using the Alw26I restriction enzyme.

RESULTS

There was no significant difference between groups in the proportions of the Ile/Ile (wild type) and Ile/Val (heterozygote) genotypes. However, the Val/Val (mutant type homozygote) was expressed in only one case (0.7%) in the perennial allergic rhinitis group, as compared with 11 cases (7.1%) in the controls (p < 0.05).

CONCLUSION

Our results indicate that the Val/Val genetic polymorphism of GSTP1 may exert some protective effects in allergic inflammation.

Intravail: highly effective intranasal delivery of peptide and protein drugs

Recent development of a new class of patented alkylsaccharide transmucosal delivery enhancement agents, collectively designated as Intravail (Aegis Therapeutics) absorption enhancers, has created opportunities for new therapeutic options across a broad spectrum of human diseases. Intravail absorption enhancers provide unsurpassed intranasal bioavailabilities, comparable to those that are achieved by injection for protein, peptide and other macromolecular therapeutics. These novel, highly effective and non-irritating excipients circumvent the two primary limitations of intranasal drug delivery, namely mucosal irritation and poor bioavailability, and offer the promise of more convenient, more effective and safer therapeutics for patients and physicians alike. For pharmaceutical companies, Intravail provides a means to capitalise on two important industry dynamics: rapidly growing industry interest in commercialising peptide and protein drugs, and increasing interest in, and use of, the intranasal route for systemic drug delivery.

Are there sex and gender differences in acute exposure to chemicals in the same setting?

We have little understanding of the influence that sex and gender may have on exposure to and measurement of occupational chemicals. If men and women are in the same physical environment, whether that be an occupational or an environmental setting, researchers need to question whether their acute exposure, as measured by administered and/or biologically effective dose, is the same. Not doing so may result in incorrect inferences being made about the risks associated with that exposure. Three critical questions arise specifically, do men and women differ in (1) their personal environments (immediate physical environments and personal attributes), (2) their absorption of the substance across the various biological barriers, and (3) the amount of active substance that reaches the target sites? Both contextual (e.g., smoking habits, diet, use of personal care products and jewellery, hobbies, stress, and use of medications) and biological (e.g., endocrine status) factors should be considered in answering these questions. Examples from the literature are provided to show that, depending on the chemical compound, there may be sex and gender differences in exposure to chemicals which can be manifested in sex differences in absorption, distribution, metabolism, storage, and excretion. An argument is developed to support the need to make information available, such as pharmacokinetic modeling studies in both men and women including appropriate age groups representing the spectrum of life stages and reproductive status.

Proteomic identification of differentially expressed proteins in the aging murine olfactory system and transcriptional analysis of the associated genes

Decline in olfactory ability has been associated with aging as well as neurodegenerative disorders. The aim of this study was to gain fundamental insight into molecular events associated with the aging olfactory system. We report a comparative proteomic analysis of the olfactory epithelium (OE) and olfactory bulb (OB) of old (80-week old) and young (6-week old) mice with further analysis of age-related differences in differentially expressed proteins at the mRNA level using real-time RT-PCR. Nine proteins in the OE and 20 in the OB were differentially expressed in old and young mice; of these, aldolase 1, peptidyl prolyl isomerase A, mitochondrial aconitase 2, mitochondrial aldehyde dehydrogenase 2 and albumin 1 were identified in the OE; and ATP synthase isoform 1, enolase 1, ferritin heavy chain, malate dehydrogenase 1, tropomyosin alpha 3 chain and dynamin 1 were identified in the OB. At the transcriptional level, aconitase 2 in the OE and ferritin heavy chain 1 in the OB were differentially expressed with aging, in concordance with the proteomic data. Our results demonstrate an altered proteomic profile of the aged murine olfactory system. The identified proteins fall into three broadly defined functional categories: (i) metabolism, (ii) transport/motility and (iii) stress response. Our transcriptional analysis provides insight into possible mechanisms by which protein expression may be regulated in the OE and OB. The results are discussed in relation to the decrement in olfactory sensitivity with aging.

Expression of cytochrome p450 and other biotransformation genes in fetal and adult human nasal mucosa

Despite recent progress in the identification and characterization of numerous nasal biotransformation enzymes in laboratory animals, the expression of biotransformation genes in human nasal mucosa remains difficult to study. Given the potential role of nasal biotransformation enzymes in the metabolism of airborne chemicals, including fragrance compounds and therapeutic agents, as well as the potential interspecies differences between laboratory animals and humans, it would be highly desirable to identify those biotransformation genes that are expressed in human nasal mucosa. In this study, a global gene expression analysis was performed to compare biotransformation enzymes expressed in human fetal and adult nasal mucosa to those expressed in liver. The identities of a list of biotransformation genes with apparently nasal mucosa-selective expression were subsequently confirmed by RNA-polymerase chain reaction (PCR) and DNA sequencing of the PCR products. Further quantitative RNA-PCR experiments indicated that, in the fetus, aldehyde dehydrogenase 6 (ALDH6), CYP1B1, CYP2F1, CYP4B1, and UDP glucuronosyltransferase 2A1 are expressed preferentially in the nasal mucosa and that ALDH7, flavin-containing monooxygenase 1, and glutathione S-transferase P1 are at least as abundant in the nasal mucosa as in the liver. The nasal mucosal expression of CYP2E1 was also detected. These findings provide a basis for further explorations of the metabolic capacity of the human nasal mucosa for xenobiotic compounds.

Characterization of the mouse olfactory glutathione S-transferases during the acute phase response

The acute phase response (APR) has been shown to alter expression and activity of biotransformation enzymes, such as the phase I cytochromes p450 and phase II glutathione S-transferases (GSTs). The cytochromes p450 and GSTs are expressed abundantly and colocalized to non-neuronal cells of the olfactory mucosa. Previous studies indicate that olfactory cytochromes p450 expression and activity is altered during periods of localized inflammation and infection. Little is understood, however, about the influence of the APR on olfactory GST enzymes. This study investigated effects of the APR on olfactory GST isozymes expression and activity in mouse olfactory mucosa after 24-hr treatment with the acute phase inducer, polyinosinic: polycytidylic acid (polyIC). Western blot analysis using antibodies directed against specific GST isoforms alpha (A1-1), micro (M1-1), and pi (P1-1) demonstrated that their expression was unaltered by polyIC treatment. In contrast, olfactory p450 2E1 expression was significantly decreased. Enzymatic activity of the olfactory GSTs toward the general substrate, 1-chloro-2,4-dinitrobenzene (CDNB) was unchanged during the APR. Analysis of olfactory glutathione content during the APR showed that it was also unaffected by polyIC. The insensitivity of these olfactory GST isoforms during the APR may play a significant role toward limiting the impact of infection and inflammation on the olfactory system.

3-Nitrotyrosine immunoreactivity in olfactory receptor neurons of patients with Alzheimer's disease: implications for impaired odor sensitivity

Olfactory sensory function is impaired in patients with the diagnosis of probable Alzheimer's disease (AD) compared to elderly controls, and the olfactory epithelium (OE) of AD patients exhibits several pathological changes characteristic of the AD brain. To confirm that the populations from whom our postmortem tissues are obtained exhibit similar decrements in sensory function, threshold testing was performed; probable AD patients had significantly higher olfactory thresholds than controls. To determine if oxidative stress contributes to decreased olfactory function in AD, we localized 3-nitrotyrosine (3-NT) immunoreactivity in OE obtained postmortem from patients with neuropathologically confirmed AD and age-matched controls with brains free of significant neurodegenerative pathology. In AD patients, immunoreactivity was localized in olfactory receptor neurons (ORNs), including dendritic knobs where ion channels that participate in sensory transduction are located, suggesting a direct mechanism for olfactory impairment. In controls, immunoreactivity occurred in blood vessel endothelium, suggesting age-related vascular dysfunction. Immunohistochemistry for CD68, a macrophage scavenger receptor, demonstrated activated macrophages, a source of free radicals contributing to 3-NT formation, in the OE of AD patients but not controls. These results demonstrate increased oxidative stress and modification of ORN proteins that may contribute directly to olfactory impairment in AD patients.

Age-related trends in gene expression in the chemosensory-nasal mucosae of senescence-accelerated mice

We have utilized high-density GeneChip oligonucleotide arrays to investigate the use of the senescence-accelerated mouse (SAM) as a biogerontological resource to identify patterns of gene expression in the chemosensory-nasal mucosa. Gene profiling in chronologically young and old mice of the senescence-resistant (SAMR) and senescence-prone (SAMP) strains revealed 133 known genes that were modulated by a three-fold or greater change either in one strain or the other or in both strains during aging. We also identified known genes in our study which based on their encoded proteins were identified as aging-related genes in the aging neocortex and cerebellum of mice as reported by Lee et al. (2000) [Nat. Genet. 25 (2000) 294]. Changes in gene profiles for chemosensory-related genes including olfactory and vomeronasal receptors, sensory transduction-associated proteins, and odor and pheromone transport molecules in the young SAMR and SAMP were compared with age-matched C57BL/6J mice. An analysis of known gene expression profiles suggests that changes in the expression of immune factor genes and genes associated with cell cycle progression and cell death were particularly prominent in the old SAM strains. A preliminary cellular validation study supported the dysregulation of cell cycle-related genes in the old SAM strains. The results of our initial study indicated that the use of the SAM models of aging could provide substantive information leading to a more fundamental understanding of the aging process in the chemosensory-nasal mucosa at the genomic, molecular, and cellular levels.

Differences in the expression of glutathione S-transferases in normal pancreas, chronic pancreatitis, secondary chronic pancreatitis, and pancreatic cancer

INTRODUCTION

In our previous study, glutathione S-transferase-pi (GST-pi), a phase II drug metabolizing enzyme, was found to be expressed in pancreatic ductal and ductular cells but not acinar cells of the normal pancreas, chronic pancreatitis, and secondary pancreatitis caused by pancreatic cancer. A greater percentage of the cells expressing GST-pi was shown in the islets of chronic pancreatitis specimens compared with the normal pancreas and secondary pancreatitis.

AIMS AND METHODOLOGY

To examine whether the increased number of islet cells expressing GST-pi and the absence in the acinar cells are compensated for by other GST isozymes, we investigated the expression of GST-alpha and GST-mu in the same specimens.

RESULTS

Unlike the distribution of GST-pi, the distribution of GST-alpha and GST-mu in islets did not show marked differences between the three groups. However, in four of 18 primary chronic pancreatitis specimens, more islet cells (approximately 25%) expressed GST-alpha than in the normal pancreas and secondary chronic pancreatitis (both approximately 10%). The reactivity of cancer cells to GST-alpha, GST-mu, and GST-pi was similar to the ductal cells in the normal pancreas, chronic pancreatitis, and secondary chronic pancreatitis. Contrary to the expression of GST-pi, no statistically significant differences were found in the distribution of GST-alpha and GST-mu in the normal pancreas, chronic pancreatitis, and secondary chronic pancreatitis.

CONCLUSION

The expression of the other GSTs does not compensate for the variation of expression of GST-pi. There was no specimen in each group that did not express at least one GST isozyme in islet, acinar, and ductal cells.

Determination of glutathione S-transferase mu and theta polymorphisms in neurological disease

1. Correlations between deletions in two glutathione S-transferase (GST) genes, GSTM1 and GSTT1 and susceptibility to Alzheimer's disease (AD), motor neuron disease (MND) and Parkinson's disease (PD) have been investigated by PCR, using primers specific for both genes. 2. It was found that males with a deletion of the GSTM1 gene were more susceptible to PD and males with a deletion of the GSTT1 gene more susceptible to MND and PD, possibly implying that environmental factors which specifically target men may be involved. Furthermore, subjects with a deletion of the GSTT1 gene were more susceptible to AD.

Metabolic capacity of nasal tissue interspecies comparisons of xenobiotic-metabolizing enzymes

High levels of xenobiotic-metabolizing enzymes occur in the nasal mucosa of all species studied. In certain species, including rats and rabbits, unique enzymes are present in the nasal mucosa. The function of these enzymes is not well understood, but it is thought that they play a role in protecting the lungs from toxicity of inhalants. The observation that several nasal xenobiotic-metabolizing enzymes accept odorants as substrates may indicate that these enzymes also play a role in the olfactory process. Xenobiotic-metabolizing enzymes were found in the nasal cavity around 15 years ago. Since that time, much has been learned about the nature of the enzymes and the substrates they accept. In the present review, this information is summarized with special attention to species differences in xenobiotic-metabolizing enzymes of the nasal cavity. Such differences may be important in interpreting the results of toxicity assays in animals because rodents are apparently more susceptible to nasal toxicity after exposure to inhalants than are humans.