Differences in MCF-7 response to endocrine disruptors in waste, superficial, and treated water from Southern Brazil

The aim of this study was to evaluate the effect of possible endocrine disruptors in surface and wastewater using a cell proliferation assay in an estrogen-responsive cell line (MCF-7). This study was conducted in the Sinos River (Brazil). The residual water was collected from a Pilot Treatment Plant (using Typha domingensis) and surface waters of the Luis Rau stream, the Sinos River, and the Water Treatment Station (WTS). After exposures (24-120 h), a Sulforhodamine B assay was performed to determine the proliferation rate. The higher increase in proliferation rate was observed with the Luiz Rau stream and the sewage treated by macrophytes in a flotation filter. The results from WTS water remained with a proliferation rate similar to the negative control at all times, suggesting that the conventional treatment is partially effective for the withdrawal of endocrine-disrupting agents. The study demonstrated the efficiency of the MCF-7 line in assessing endocrine disruption caused by wastewater and surface water samples. Our results indicate that conventional water treatment can partially remove the polluting load of endocrine disruptors, minimizing their environmental and public health impacts. Besides, it demonstrates the need to expand sanitary services to improve the population's quality of life.

Evaluation of oxidative stress and its association with drug therapy in inpatients treated for cocaine dependence

The use of cocaine affects several systems and organs of the human body and the consumption of this substance leads to an increase in the production of reactive oxygen species, and to the reduction of antioxidant defenses. The aim of this study was to evaluate the oxidative stress (OS), biochemical and hematological parameters in patients hospitalized for treatment of cocaine addiction, comparing levels at hospital admission and discharge. Forty patients were included in the study. OS was evaluated using catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GPx), total antioxidant power (FRAP), malondialdehyde (MDA), and sulfhydryl group (GS). The medications used during hospitalization were registered and their influence on the parameters of OS was analyzed. After the hospitalization period, there was an increase in GGT levels, a reduction in SOD activity, and an increase in GPx activity and FRAP levels. Carbamazepine users had higher SOD values and lower FRAP values at hospital discharge. The use of chlorpromazine caused differences in creatinine and gamma-glutamyltransferase (GGT) serum leves, and the levels of glutamic oxalacetic transaminase (TGO), MDA, and FRAP were increased at hospital discharge. Haloperidol and thiamine during hospitalization interfered with alkaline phosphatase levels. The use of risperidone caused an increase in the levels of SOD, and folic acid use was associated with lower levels of GPx and higher levels of glutamic-pyruvic transaminase (TGP) and alkaline phosphatase. Drug rehabilitation treatment was effective in decreasing oxidative damage represented by the reduction of biological markers.

Iota-carrageenan/xyloglucan/serine powders loaded with tranexamic acid for simultaneously hemostatic, antibacterial, and antioxidant performance

This study sought to prepare powder hemostats based on iota-carrageenan (ιC), xyloglucan (XYL), l-serine (SER), and tranexamic acid (TA). The powder form was chosen because it enables the hemostat to be used in wounds of any shape and depth. The powder hemostats showed irregular shapes and specific surface areas ranging from 34 to 46 m²/g. Increasing TA amount decreases the specific surface area, bulk density, water and blood absorption, and the antibacterial activities of the powder hemostats, but not the water retention ability. Conversely, in vitro biodegradation was positively impacted by increasing the TA content in the powder hemostats. In both the in vitro and in vivo tests, powder hemostats showed reduced bleeding time, significant adhesion of red blood cells, great hemocompatibility, moderate antioxidant activity, and high biocompatibility. These findings shed new light on designing powder hemostats with intrinsic antibacterial and antioxidant activity and excellent hemostatic performance.

Cytotoxic and genotoxic effects induced by associated commercial glyphosate and 2,4-D formulations using the Allium cepa bioassay

Studies assessing the toxicity of glyphosate and 2,4-dichlorophenoxyacetic acid mixture are scarce. The aim of this study was to evaluate the cytotoxicity and genotoxicity of the mixture of these herbicides using Allium cepa. Roots were exposed to glyphosate (1.56 and 11.66 mg mL-1), 2,4-D (0.28 and 17.5 mg mL-1) and mixture for 24 h, based on the average concentration applied in the field and the acute reference dose (ARfD) established in Brazil. Both isolated and associated herbicides induced a significative decrease in mitotic index (MI) (P < 0.0001) in all tested concentrations. Regarding the genotoxicity results, 2,4-D and the mixture showed, at concentrations applied in the field, a significative increase of chromosomal anomalies (CA) index compared to control (P < 0.0001) and glyphosate (P = 0.024 and P = 0.0002, respectively). All tested groups from the ARfD showed a significative difference compared to the control group (P < 0.0001), as well as glyphosate and 2,4-D isolated compared to the mixture (P = 0.0005 and P < 0.0001, respectively). The most observed CA were apoptotic bodies, giant cells, and nuclear erosions. We emphasize the need for further studies assessing the toxicity of these herbicides' mixture due to the distinct effects caused in different organisms.

Pervasive transmission of E484K and emergence of VUI-NP13L with evidence of SARS-CoV-2 co-infection events by two different lineages in Rio Grande do Sul, Brazil

Emergence of novel SARS-CoV-2 lineages are under the spotlight of the media, scientific community and governments. Recent reports of novel variants in the United Kingdom, South Africa and Brazil (B.1.1.28-E484K) have raised intense interest because of a possible higher transmission rate or resistance to the novel vaccines. Nevertheless, the spread of B.1.1.28 (E484K) and other variants in Brazil is still unknown. In this work, we investigated the population structure and genomic complexity of SARS-CoV-2 in Rio Grande do Sul, the southernmost state in Brazil. Most samples sequenced belonged to the B.1.1.28 (E484K) lineage, demonstrating its widespread dispersion. We were the first to identify two independent events of co-infection caused by the occurrence of B.1.1.28 (E484K) with either B.1.1.248 or B.1.91 lineages. Also, clustering analysis revealed the occurrence of a novel cluster of samples circulating in the state (named VUI-NP13L) characterized by 12 lineage-defining mutations. In light of the evidence for E484K dispersion, co-infection and emergence of VUI-NP13 L in Rio Grande do Sul, we reaffirm the importance of establishing strict and effective social distancing measures to counter the spread of potentially more hazardous SARS-CoV-2 strains.

Impact of post-tanning chemicals on the pollution load of tannery wastewater

The leather industry uses a large amount of chemicals to transform a raw hide into finished leather. Chemicals are not fully taken up by leather and thus end up in tannery wastewater. Physicochemical and toxicological characterization of tannery effluents has been widely assessed. However, the characterization of processing chemicals and their relation to the pollution load of effluents remains unknown. Thus, this study aimed to assess a physicochemical and cytotoxic characterization of chemicals used in the leather post-tanning process and to evaluate the contribution of each chemical to the pollution load of raw wastewater. This study was performed using a leather post-tanning formulation applied by a large tannery located in Brazil. Deacidulation agents caused high conductivity and dissolved solids in wastewater. Retanning agents (natural and synthetic tannins) were responsible for the largest inorganic pollution load, and synthetic tannins were more toxic than natural ones. Fatliquoring agents released the highest chemical oxygen demand load in wastewater and they were the chemical group that presented the highest toxicity. Fixing agent and black dye provided inorganic pollution load to wastewater, and nitrogen pollution of wastewater was mainly related to the neutralizing retanner and the black dye.

Determination of oxidative stress parameters in fluoxetine users

Fluoxetine (FLU), a selective serotonin reuptake inhibitor, is the first line in depression treatment and it is involved in oxidative stress (OE). Thus, this study aimed to analyze the OE parameters in patients diagnosed with depression and treated with FLU. Were evaluated 121 volunteers divided into two groups: 58 fluoxetine users (with major depression) and 63 non-fluoxetine users (control group, without major depression). The OE was evaluated by determining the levels of malondialdehyde (MDA), total antioxidant power (FRAP) and activity of antioxidant enzymes glutathione peroxidase (GPx) and superoxide dismutase (SOD). MDA, FRAP, GPx and SOD were dosed in plasma. The influence of age, smoking, alcoholism, comorbidities, use of another drugs and antioxidants in the OE were evaluated. The results were compared between the groups. In relation to the fluoxetine daily dose, MDA presented higher levels in patients using 20 mg daily FLU when compared to the control group, as well as the activity of the GPx enzyme and the FRAP levels. In this way, the use of fluoxetine may interfere with the OE parameters, causing an increase in OE levels.

Histopathological, genotoxic, and behavioral damages induced by manganese (II) in adult zebrafish

Manganese is a metal often found as an environmental pollutant and very associated with neurological disorders when in high concentrations. However, little is known about the effects that this contaminant can cause when in environmentally relevant concentrations and occurrence, that is, much lower than those commonly studied. So, the aim of the study was to evaluate the effects that environmentally relevant concentrations of this metal would cause in different zebrafish organs (brain, liver, and blood). Acute 96-h and chronic 30-day exposures were performed using the manganese chloride salt as a pollutant. Behavioral alterations of anxiogenic type were observed in the animals after chronic exposures to 4.0 mg L^-1 MnCl₂, which traveled a greater distance at the bottom of the aquarium. This may be associated with neuronal damages in the telencephalic region responsible for motor and cognitive activity of the fish, observed in animals from the same exposure. In addition, hepatic histopathological damage as vacuolization of hepatocytes and genotoxic damage, identified by comet assay and micronucleus test, was also observed after acute and chronic exposure, especially at the highest pollutant concentrations (8.0 and 16.0 mg L^-1 in acute exposure, and 4.0 mg L^-1 in chronic exposure. The study reinforces the risk that environmental pollutants pose to the ecosystem, even in low concentrations.

Polymer-based wafers containing in situ synthesized gold nanoparticles as a potential wound-dressing material

Polymer-based wafers containing gold nanoparticles (AuNP) were prepared using κ-carrageenan (κC), locust bean gum (LBG) and polyvinyl alcohol (PVA) at ratios of 42/22/13% ^w/_w and 35/15/17% ^w/_w. The synthesized AuNPs were evaluated for their particle size and morphology. The produced wafers containing AuNPs were investigated for their physicochemical, morphological, mechanical, and swelling properties. In addition, bacterial barrier activity and in vitro cytotoxicity were also evaluated in this study. The AuNPs obtained were spherical in shape (~ 10-15 nm in diameter) and exhibited a single bell-shaped UV-vis absorption band centered ~ 540 nm. FT-IR spectra of the wafers containing AuNPs exhibited a shift of ν(O=S=O) absorption band toward a lower wavenumber and a shift of ν(OH) absorption band toward a higher wavenumber due to the coordination of OH groups to AuNPs and their interaction with O=S=O groups of κC, respectively. SEM images confirmed the porous structure of the produced wafers, being the surface area, mechanical properties, and swelling behavior directly affected by changing both the initial amount of [Au⁺³] and the composition of the wafers. Lastly, the produced wafers showed non-toxicity to NIH-3T3 fibroblast cells, and they also serve as a bacterial barrier. These findings endorsed the claim that the produced wafers containing AuNPs could be a promising material for wound dressing applications.

Toxicity of Glandularia selloi (Spreng.) Tronc. leave extract by MTT and neutral red assays: influence of the test medium procedure

Cytotoxicity assays using cell cultures may be an alternative to assess biological toxicity of plant extracts with potential phytotherapeutic properties. This study compared three methods to prepare culture media for the exposure of Vero cells to plant extracts. Leaves of Glandularia selloi (Spreng.) Tronc. were used to prepare culture medium with aqueous extract, extract in culture medium and methanol extract. Toxicity was assessed using the MTT and neutral red (NR) assays. In general, alterations in the cellular functions were found in all extracts and assays. Cytotoxic effect occurred at lower doses in aqueous extract and the range of effect of the methanol extract was small. The procedure of preparing the test medium has an effect on the outcome of the assay. Cytotoxicity of plant extract can be assessed by MTT and NR assays. Aqueous extract added to the culture medium presented the best profile to assess cytotoxicity.

Monitoring the Genotoxic and Cytotoxic Potential and the Presence of Pesticides and Hydrocarbons in Water of the Sinos River Basin, Southern Brazil

The Sinos River is one of the most polluted rivers in Brazil. The purpose of this work was to monitor the presence of some pesticides and hydrocarbons as well as the genotoxic and cytotoxic potential on HEp-2 cells from water samples collected at seven sites in the Sinos River Basin (SRB), southern Brazil. Nine samples were taken from the three main rivers in the SRB and used as a solution to dilute the HEp-2 cell culture medium after microfiltration. Twenty-four pesticides and 19 hydrocarbons were measured. Cytotoxicity was assessed by methyl thiazolyl tetrazolium (MTT) and neutral red (NR) assays, in which cells were exposed to different concentrations of the water samples for 24 h. Genotoxicity of the microfiltrated raw water samples was assessed by comet assay after 6 and 24 h of exposure. Among the chemicals analyzed, only the 2,4-D, dichloromethane, tetrachloroethene, chloroform, bromodichloromethane, styrene, and toluene were detected, but they were all lower than the limit established by Brazilian regulations. Twenty samples from a total of 60 had a cytotoxic effect in the MTT assay and 30 in the NR assay. The comet assay indicated the presence of genotoxic substances in the water at the seven locations monitored. Temporal and spatial variation was observed in the cytotoxicity and genotoxicity assays. Results indicated that the water in all stretches of the SRB is contaminated and it can cause harmful effects to humans and to the aquatic biota. This HEp-2 cell-line approach can be an additional tool for environmental monitoring.

Thirdhand smoke: when the danger is more than you can see or smell

Recent discussion has focused on another form of exposure to tobacco - thirdhand smoke (THS) - consisting of residual pollutants from cigarette smoke that remain in environments. The main concern with THS is based on the presence and persistence of many toxic compounds, some specific nitrosamines from tobacco that have carcinogenic activity. Little is known about THS, and few people are aware of its existence and potential health repercussions, thus highlighting the need to shed light on the subject and incorporate it into the public health debate, as was done with passive smoking several years ago. THS is a form of passive smoking, together with secondary or involuntary exposure to cigarette smoke. Recentemente, passou a ser discutida mais uma forma de exposição ao tabaco - thirdhand smoke (THS) - que consiste nos poluentes residuais da fumaça de cigarro que permanecem nos ambientes. A principal preocupação com o THS é embasada na presença e longa persistência de muitos compostos tóxicos, algumas nitrosaminas específicas do tabaco que têm atividade carcinogênica. Além de se saber pouco sobre o THS, poucos sabem de sua existência e preocupante repercussão na saúde. Coloca-se em destaque a necessidade de trazê-lo à luz e incluí-lo nas discussões, assim como foi feito com o tabagismo passivo alguns anos atrás, até mesmo porque o THS se caracteriza como uma forma de tabagismo passivo junto à exposição secundária ou involuntária da fumaça de cigarro.

Thirdhand tobacco smoke: procedures to evaluate cytotoxicity in cell cultures

The risks associated to tobacco smoking are not ceased with smoke extinction. Many toxic compounds remain in the environment after the cigarette is extinguished and accumulated in the air or on surfaces. However, little is known about the risks of this exposure. The aim of this study was to evaluate procedures to collect thirdhand smoke (THS) and prepare the samples to perform three in vitro toxicity tests. Cellulose papers and cotton wipes were used to impregnate with nicotine solution and smoke cigarette in a chamber or in smoker's home. Samples were immersed in methanol or Dulbecco's modified Eagle's medium (DMEM) to expose Hep-2 cells. MTT, neutral red uptake (NRU) and trypan blue assays were performed. The concentration of nicotine in DMEM extract of THS in paper and cotton was similar to those in methanol extract (p > 0.05). Alterations in the mitochondrial and lysosomal functions were found in both paper and cotton samples; however, the cytotoxic effect was not always observed. There was a decrease of 21-31% in MTT assay and 38-56% in NRU assay (p < 0.003). There was a dose-response relationship between the amount of cigarettes and lysosomal viability; the correlation was higher for cotton samples (r = -0.843, p < 0.001). As a dose-response relationship was found only in NRU assay, this test may be a more suitable choice rather than the MTT assay. Paper and wipe sampling can be reliable markers of tobacco smoke contamination. Moreover, these materials, if properly prepared, can be used as substrate providers to perform cellular assays.

Cytotoxicity assays as tools to assess water quality in the Sinos River basin

<p>Cytotoxicity assays using cell cultures may be an alternative to assess biological toxicity of surface waters and may help to improve the control of water quality. This study compared two methods to prepare culture media for the exposure of Hep-2 cells to water samples collected from the Rolante River, an important affluent of the Sinos River. The toxicity was evaluated using the MTT and neutral red assays. Two methods were used to prepare culture media. In method 1, the sample was diluted at 1:1, 1:10, 1:100, 1:1000, 1:10.000 (v/v, sample/medium) in a standard culture medium; in method 2, water samples were used as the solvent for the culture medium, which was prepared at concentrations of 100, 80, 60, 40 and 20%. Semi-confluent cultures were then exposed to the media test for 24 hours, and cytotoxicity was determined immediately using the MTT and NR assays. Mitochondrial activity (MTT) was significantly lower at all concentrations in both methods, except at 1:1000 in method 1. However, the lysosome viability (NR) results revealed cytotoxicity only in the 1:1 sample of method 1. Both culture preparation methods were efficient and sensitive to the MTT assay, but method 2 seemed to be more adequate for the NR assay. The Rolante River has cytotoxic contaminants to Hep-2 cells, which may be one of the explanations for the poor water quality of the Sinos River basin.</p>

Evaluation of genotoxicity and cytotoxicity of water samples from the Sinos River Basin, southern Brazil

<p>Some water bodies in the Sinos River Basin (SRB) have been suffering the effects of pollution by residential, industrial and agroindustrial wastewater. The presence of cytotoxic and genotoxic compounds could compromise the water quality and the balance of these ecosystems. In this context, the research aimed to evaluate the genotoxicity and cytotoxicity of the water at four sites along the SRB (in the cities of Santo Antônio da Patrulha, Parobé, Campo Bom and Esteio), using bioassays in fish and cell culture. Samples of surface water were collected and evaluated <italic>in vitro</italic> using the <italic>Astyanax jacuhiensis</italic> fish species (micronucleus test and comet assay) and the Vero lineage of cells (comet assay and cytotoxicity tests, neutral red - NR and tetrazolium MTT). The micronucleus test in fish showed no significant differences between the sampling sites, and neither did the comet assay and the MTT and NR tests in Vero cells. The comet assay showed an increase in genetic damage in the fish exposed to water samples collected in the middle and lower sections of the basin (Parobé, Campo Bom and Esteio) when compared to the upper section of the basin (Santo Antônio da Patrulha). The results indicate contamination by genotoxic substances starting in the middle section of the SRB.</p>

Acompanhamento farmacoterapêutico em pacientes dislipidêmicos de um lar de idosos da cidade de Novo Hamburgo-RS

INTRODUÇÃO: A partir do último século, observou-se aumento na expectativa de vida e na incidência de patologia na população idosa, principalmente doenças crônicas. OBJETIVO: Avaliar o efeito do acompanhamento farmacoterapêutico (AF) em pacientes dislipidêmicos de um lar de idosos da cidade de Novo Hamburgo, RS. METODOLOGIA: Trata-se de estudo quantitativo, observacional com delineamento longitudinal retrospectivo, que avaliou 50 pacientes idosos residentes de um lar geriátrico (80,2 ± 7,64 anos, 32 mulheres). Foi avaliado o perfil lipídico desses pacientes (colesterol total, triglicerídeos, HDL e LDL) antes e após AF de um ano. A análise dos resultados ocorreu por meio de estatística descritiva e teste t Student ou U de Mann Whitney para amostras pareadas. RESULTADOS: 56% dos pacientes apresentaram alteração no perfil lipídico no início do estudo e, 30% ao final, ocorrendo significativa melhora após o AF. Além disso, os níveis de colesterol total apresentaram diminuição favorável após um ano de acompanhamento (206 ± 53 vs. 180 ± 43 mg/dL; P = 0,009). A maioria dos pacientes que apresentou diagnóstico de dislipidemia utilizava medicamentos há pelo menos três meses para o tratamento dessa patologia (estatinas e fibratos). A maioria desses pacientes utilizava os medicamentos de forma correta. CONCLUSÃO: Conclui-se que os pacientes tiveram melhora no seu perfil lipídico após um ano de acompanhamento.

Acompanhamento farmacoterapêutico em idosos hipertensos residentes em um lar geriátrico, localizado na Região do Vale dos Sinos, Rio Grande do Sul, Brasil

INTRODUÇÃO: A hipertensão arterial sistêmica (HAS) é um dos problemas de saúde de maior prevalência, afetando cerca de 600 milhões de pessoas em todo mundo. No Brasil, aproximadamente 65% da população idosa é portadora desta doença. Objetivo: Avaliar a resposta farmacoterapêutica em idosos hipertensos, residentes em um lar geriátrico, após acompanhamento farmacoterapêutico e intervenções farmacêuticas. METODOLOGIA: Trata-se de estudo quantitativo, observacional com delineamento longitudinal retrospectivo. Participaram 31 (62%) idosos do total de 50 indivíduos (acima de 60 anos), de ambos os sexos e com HAS diagnosticada. Avaliaram-se as médias mensais das pressões sistólica, diastólica e pressão arterial média, no período de setembro/2008 a julho/2010. A análise dos resultados ocorreu por meio de estatística descritiva e teste t de Student para amostras pareadas. RESULTADOS: Quanto ao tratamento medicamentoso para HAS, predominou o uso de Inibidores da ECA (71%) e diuréticos tiazídicos (41,9%); 61,3% dos pacientes em estudo fazem tratamento farmacológico em associação de fármacos anti-hipertensivos. Não foram observadas interações medicamentosas clinicamente relevantes entre os fármacos anti-hipertensivos e as demais classes terapêuticas utilizadas pelos idosos. Houve queda nas médias pressóricas, assim como no número de pacientes com pressão arterial alterada. CONCLUSÃO: O decréscimo das médias pressóricas pode ser atribuído a diversos fatores e, após o acompanhamento farmacoterapêutico desses pacientes, os níveis de pressão arterial melhoraram.

Relation between CYP2C19 phenotype and genotype in a group of Brazilian volunteers

The CYP2C19 gene presents polymorphism affecting the pharmacokinetics of several drugs of clinical importance. The purpose of this study was to investigate the correlation between CYP2C19 genotype and metabolic phenotype in a group of 38 Brazilian volunteers, evaluating the phenotype prediction capacity of the genotyping procedure. For CYP2C19 phenotyping, omeprazole was used as the probe drug, using the hydroxylation metabolic ratio as the phenotypic indicator. Venous blood samples were drawn before and three hours after an oral administration of 20 mg omeprazole. The plasma concentrations of omeprazole and hydroxy-omeprazole were determined by high performance liquid chromatography. The genotyping assay was carried out using a Real-Time-PCR-based assay, identifying the alleles *1 (completely functional), *2, *3 and *4 (null). The phenotyping procedure estimated the presence of 4 poor, 34 extensive and 1 ultra-extensive metabolizer. The genotyping identified 4 poor, 23 extensive and 11 intensive metabolizers. The groups of volunteers classified according to the number of active alleles of CYP2C19 had significant differences in the metabolic ratios of omeprazole hydroxylation. However, volunteers exhibiting the same number of active alleles presented different phenotypes. Therefore, the phenotyping of CYP2C19 is a more promising alternative to dose individualization of CYP2C19 substrate drugs.

Synthesis and transport of different sphingomyelin species in rat Sertoli cells

Cellular phospholipids of Sertoli cells from immature rats were labeled with [14C]-choline. Two sphingomyelin bands (SM1 and SM2) were identified by TLC. The incorporation of [14C]-choline over a 45 h period of incubation demonstrated that there are differences in labeling kinetics between SM1 and SM2. The subcellular location of SM1 and SM2 was investigated by accessibility to bacterial sphingomyelinase. The results showed the existence of two SM pools in Sertoli cells, but an equal cellular distribution of SM1 and SM2. SM2 is characterized by a relatively high content of unsaturated fatty acids. The inhibition of vesicular flow by monensin determines a decrease of about 60-70% in incorporation into SM1 and SM2, suggesting the existence of at least two sites of sphingomyelin synthesis. Pulse-chase and time-course experiments indicated a phosphatidylcholine --> SM precursor product relationship and differences in kinetic properties between SM1 and SM2. Resynthesis experiments showed that monensin had only a partial inhibitory effect on SM1 resynthesis, and a second sphingomyelinase treatment demonstrated that the resynthesized fraction reached the outer leaflet of the plasma membrane. The 60-70% inhibition of SM synthesis by monensin showed that the trans-Golgi cisternae and the trans-Golgi network are the most likely sites of bulk SM synthesis, and that about 15% of SM was synthesized in the cis/medial Golgi apparatus. Additionally the results indicated that plasma membrane SM synthase activity could be the site of about 15% of SM synthesis in Sertoli cells.

De novo synthesis and recycling pathways of sphingomyelin in rat Sertoli cells

Sertoli cells from 19-day-old rats have two molecular species of sphingomyelin (SM1 and SM2) with different kinetic characteristics and fatty acid composition. Here, we have studied the incorporation of [14C]-choline and [14C]-palmitic acid into SM in presence or absence of fumonisin B1, an inhibitor of ceramide synthesis, and beta-chloroalanine, an inhibitor of sphinganine synthesis. The contributions of de novo synthesis and recycling pathways were estimated by analysis of the inhibition caused by these drugs. SM1 was synthesized more by sphingosine recycling, and SM2 was synthesized principally by ceramide recycling than SM1. De novo synthesis seems to be important for the two SM types, but our results showed that this pathway is more extensively utilized by SM2. In conclusion, using Sertoli cell cultures, we have shown for the first time that in the same cell different molecular species of SM are synthesized by different pathways.