Long term behavior of dexamethasone-loaded cochlear implants: In vitro & in vivo.

The aim of this study was to better understand the long term behavior of silicone-based cochlear implants loaded with dexamethasone: in vitro as well as in vivo (gerbils). This type of local controlled drug delivery systems offers an interesting potential for the treatment of hearing loss. Because very long release periods are targeted (several years/decades), product optimization is highly challenging. Up to now, only little is known on the long term behavior of these systems, including their drug release patterns as well as potential swelling or shrinking upon exposure to aqueous media or living tissue. Different types of cylindrical, cochlear implants were prepared by injection molding, varying their dimensions (being suitable for use in humans or gerbils) and initial drug loading (0, 1 or 10%). Dexamethasone release was monitored in vitro upon exposure to artificial perilymph at 37 °C for >3 years. Optical microscopy, X-ray diffraction and Raman imaging were used to characterize the implants before and after exposure to the release medium in vitro, as well as after 2 years implantation in gerbils. Importantly, in all cases dexamethasone release was reliably controlled during the observation periods. Diffusional mass transport and limited drug solubility effects within the silicone matrices seem to play a major role. Initially, the dexamethasone is homogeneously distributed throughout the polymeric matrices in the form of tiny crystals. Upon exposure to aqueous media or living tissue, limited amounts of water penetrate into the implant, dissolve the drug, which subsequently diffuses out. Surface-near regions are depleted first, resulting in an increase in the apparent drug diffusivity with time. No evidence for noteworthy implant swelling or shrinkage was observed in vitro, nor in vivo. A simplified mathematical model can be used to facilitate drug product optimization, allowing the prediction of the resulting drug release rates during decades as a function of the implant's design.

Glycolysis Inhibition as a Strategy for Hepatocellular Carcinoma Treatment?

Hepatocellular carcinoma (HCC) is the most frequently detected primary malignant liver tumor, representing a worldwide public health problem due to its high morbidity and mortality rates. The HCC is commonly detected in advanced stage, precluding the use of treatments with curative intent. For this reason, it is crucial to find effective therapies for HCC. Cancer cells have a high dependence of glycolysis for ATP production, especially under hypoxic environment. Such dependence provides a reliable possible strategy to specifically target cancer cells based on the inhibition of glycolysis. HCC, such as other cancer types, presents a clinically well-known upregulation of several glycolytic key enzymes and proteins, including glucose transporters particularly glucose transporter 1 (GLUT1). Such enzymes and proteins constitute potential targets for therapy. Indeed, for some of these targets, several inhibitors were already reported, such as 2-Deoxyglucose, Imatinib or Flavonoids. Although the inhibition of glycolysis presents a great potential for an anticancer therapy, the development of glycolytic inhibitors as a new class of anticancer agents needs to be more explored. Herein, we propose to summarize, discuss and present an overview on the different approaches to inhibit the glycolytic metabolism in cancer cells, which may be very effective in the treatment of HCC.

Ultrasound Measurements of Fetal Thyroid: Reference Ranges from a Cohort of Low-Risk Pregnant Women.

BACKGROUND: Adequate thyroid function is essential for normal growth and development of the fetus. Sonographic recognition of alterations in fetal thyroid dimensions may be the first sign of thyroid dysfunction, permitting early diagnosis and intervention. The main goal of this study was to build curves with reference values for ultrasound measurements of the fetal thyroid from 14 to 40 weeks of gestation. METHODS: This is a prospective longitudinal study of 90 Brazilian pregnant women, complementary to a cohort multicentre study named "WHO multicentre study for the development of growth standards from fetal life to childhood: the fetal component." Pregnant women without any pre-existing conditions that might affect fetal growth received antenatal care from the first trimester until childbirth, undergoing serial ultrasound evaluations of the fetus, including the thyroid. Longitudinal, anteroposterior, and transverse diameters of both thyroid lobes were measured in the fetus. Fetal thyroid lobe volume was also estimated. By quantile regression analysis, reference curves of measurements were fitted according to the gestational age. RESULTS: A reference standard of thyroid growth was defined during pregnancy by fitting curves of its measurements. Reference values for the 10th, 50th, and 90th centiles of fetal thyroid measurements (longitudinal, anteroposterior, transverse diameters, and lobe volume) were defined, from 14 to 40 weeks of gestation. CONCLUSION: We provided a reference curve of optimal thyroid development in a low-risk population that can be used as a standard of comparison to diagnose deviations from the norm. In addition, we demonstrated an alternative and simplified method for early recognition of thyroid morphological alterations by an individualized technique to evaluate the thyroid lobes.

Expanded equine cumulus-oocyte complexes exhibit higher meiotic competence and lower glucose consumption than compact cumulus-oocyte complexes.

Equine cumulus-oocyte complexes (COCs) are classified as compact (cCOC) or expanded (eCOC) and vary in their meiotic competence. This difference could be related to divergent glucose metabolism. To test this hypothesis in the present study, eCOCs, cCOCs and expanded or compact mural granulosa cells (EC and CC respectively) were matured in vitro for 30h, at which time maturation rate, glucose metabolism and the expression of genes involved in glucose transport, glycolysis, apoptosis and meiotic competence were determined. There were significant differences between eCOCs and cCOCs in maturation rate (50% vs 21.7% (n=192 and 46) respectively; P<0.001), as well as mean (±s.e.m.) glucose consumption (1.8±0.5 vs 27.9±5.9 nmol per COC respectively) and pyruvate (0.09±0.01 vs 2.4±0.8 nmol per COC respectively) and lactate (4.7±1.3 vs 64.1±20.6 nmol per COC respectively; P<0.05 for all) production. Glucose consumption in EC and CC did not differ significantly. Expression of hyaluronan-binding protein (tumour necrosis factor alpha induced protein 6; TNFAIP6) was increased in eCOCs and EC, and solute carrier family 2 member 1 (SLC2A1) expression was increased in eCOCs, but there were no differences in the expression of glycolysis-related enzymes and solute carrier family 2 member 3 (SLC2A3) between the COC or mural granulosa cell types. The findings of the present study demonstrate that metabolic and genomic differences exist between eCOCs and cCOCs and mural granulosa cells in the horse.

Translation and cultural adaptation into Brazilian culture of type 1 diabetes distress scale.

BACKGROUND: Diabetes related distress is common in type 1 diabetes patients (T1D). High levels of diabetes distress are related to poor metabolic control. An instrument to evaluate diabetes distress in T1D patients is "type 1 diabetes scale-T1DDS". The aim of this study was to translate and culturally adapt the T1DDS into Brazilian culture. METHODS: T1DDS scale was translated into Portuguese. Back translation was performed and evaluated by a specialists committee. Pre-test was performed with 40 T1D outpatients at State University of Campinas hospital. Internal consistency, external consistency and re-test were performed. RESULTS: 72% women, mean age: 32, 1 ± 9, 7 years, mean diabetes duration: 15, 8 ± 9, 1 years, mean scholarity: 11, 5 ± 3, 6, glycosylated hemoglobin mean: 9 ± 2%. Internal consistency: Cronbach alpha of T1DDS Brazilian version was 0.93. External consistency: Spearman's coefficient between T1DDS and PAID, Brazilian version, was 0.7781; (p < 0.0001). CONCLUSIONS: The T1DDS Brazilian version is a reliable tool to evaluate diabetes distress in T1D patients in the Brazilian Population. This tool can be useful in clinical care and to identify patiens at risk and in need for psychosocial intervention.

Oral fish oil positively influences nutritional-inflammatory risk in patients with haematological malignancies during chemotherapy with an impact on long-term survival: a randomised clinical trial.

BACKGROUND: Studies suggest that the ingestion of fish oil (FO), a source of the omega-3 polyunsaturated fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), can reduce the deleterious side-effects of chemotherapy. The aim of this randomised clinical trial was to evaluate the effect of supplementation with oral FO for 9 weeks on nutritional parameters and inflammatory nutritional risk in patients with haematological malignancies during the beginning of chemotherapy. METHODS: Twenty-two patients with leukaemia or lymphoma were randomised to the unsupplemented group (UG) (n = 13) or supplemented group (SG) (n = 9). SG received 2 g/day of fish oil for 9 weeks. Nutritional status, serum acute-phase proteins and plasma fatty acids were evaluated before (T0) and after (T1) the intervention period. Data were analysed using two models; model 1, comprising data from all patients included in the study, and model 2, comprising data from UG patients with no increase in the proportions of EPA and DHA in plasma and data from SG patients showing an at least 100% increase in plasma EPA and DHA. RESULTS: SG showed an increased plasma proportion of EPA and DHA in both models. In model 2, C-reactive protein (CRP) and CRP/albumin ratio showed larger reductions in the SG. Overall long-term survival in both models (465 days after the start of the chemotherapy) was higher in the group ingesting fish oil (P < 0.05). CONCLUSIONS: These findings indicate an improved nutritional-inflammatory risk and potential effects on long-term survival in patients with haematological malignancies supplemented with FO during the beginning of chemotherapy.

Obesogens and male fertility.

In the last decades, several studies evidenced a decrease in male fertility in developed countries. Although the aetiology of this trend in male reproductive health remains a matter of debate, environmental compounds that predispose to weight gain, namely obesogens, are appointed as contributors because of their action as endocrine disruptors. Obesogens favour adipogenesis by an imbalance of metabolic processes and can be found virtually everywhere. These compounds easily accumulate in tissues with high lipid content. Obesogens change the functioning of male reproductive axis, and, consequently, the testicular physiology and metabolism that are pivotal for spermatogenesis. The disruption of these tightly regulated metabolic pathways leads to adverse reproductive outcomes. Notably, adverse effects of obesogens may also promote disturbances in the metabolic performance of the following generations, through epigenetic modifications passed by male gametes. Thus, unveiling the molecular pathways by which obesogens induce toxicity that may end up in epigenetic modifications is imperative. Otherwise, a transgenerational susceptibility to metabolic diseases may be favoured. We present an up-to-date overview of the impact of obesogens on testicular physiology, with a particular focus on testicular metabolism. We also address the effects of obesogens on male reproductive parameters and the subsequent consequences for male fertility.

Pioglitazone increases the glycolytic efficiency of human Sertoli cells with possible implications for spermatogenesis.

Pioglitazone is a synthetic agonist for the nuclear receptor peroxisome proliferator-activated receptor γ used to treat type 2 diabetes mellitus. Recently we reported that antidiabetic drugs regulate the nutritional support of spermatogenesis by Sertoli cells. Herein, we investigate the effects of pioglitazone on human Sertoli cells metabolism. Human Sertoli cells were cultured in the presence of pioglitazone (1, 10, 100µM). Protein levels of phosphofructokinase 1, lactate dehydrogenase, hexokinase, glucose transporters (GLUT1, GLUT2, GLUT3), monocarboxylate transporter 4 and oxidative phosphorylation complexes were determined by Western blot. Lactate dehydrogenase and alanine aminotransferase activity were assessed and metabolite production and consumption determined by proton nuclear magnetic resonance. Mitochondrial membrane potential was also determined. Glucose consumption more than doubled in human Sertoli cells stimulated with pioglitazone 100µM. Mitochondrial complex II protein levels increased 50% with exposure to pioglitazone (100µM) in human Sertoli cells, though mitochondrial membrane potential was decreased by 32%. The pharmacological concentration of pioglitazone (10µM) almost doubled lactate production and established crucial correlations among key intervenient of glycolysis. Moreover, in the same concentration, alanine aminotransferase decreased more than 80%. Our results suggest that pioglitazone (10µM) increases the efficiency of the glycolytic flux and lactate production by human Sertoli cells, which is essential to sustain and preserve the spermatogenic event. Thus, pioglitazone may improve male fertility and thus, be considered a suitable antidiabetic drug for men in reproductive age.

Ghrelin acts as energy status sensor of male reproduction by modulating Sertoli cells glycolytic metabolism and mitochondrial bioenergetics.

Ghrelin is a growth hormone-releasing peptide that has been suggested to interfere with spermatogenesis, though the underling mechanisms remain unknown. We studied the effect of ghrelin in human Sertoli cells (hSCs) metabolic phenotype. For that, hSCs were exposed to increasing concentrations of ghrelin (20, 100 and 500 pM) mimicking the levels reported in obese, normal weight, and severely undernourished individuals. The metabolite production/consumption was determined. The protein levels of key glycolysis-related transporters and enzymes were assessed. The lactate dehydrogenase (LDH) activity was measured. Mitochondrial complexes protein levels and mitochondria membrane potential were also measured. We showed that hSCs express the growth hormone secretagogue receptor. At the concentration present in the plasma of normal weight men, ghrelin caused a decrease of glucose consumption and mitochondrial membrane potential in hSCs, though LDH activity and lactate production remained unchanged, illustrating an alteration of glycolytic flux efficiency. Exposure of hSCs to levels of ghrelin found in the plasma of severely undernourished individuals decreased pyruvate consumption and mitochondrial complex III protein expression. All concentrations of ghrelin decreased alanine and acetate production by hSCs. Notably, the effects of ghrelin levels found in severely undernourished individuals were more pronounced in hSCs metabolic phenotype highlighting the importance of a proper eating behavior to maintain male reproductive potential. In conclusion, ghrelin acts as an energy status sensor for hSCs in a dose-dependent manner, showing an inverse association with the production of lactate, thus controlling the nutritional support of spermatogenesis.

Expression of Estrogen Receptors Alpha (ER-α), Beta (ER-ß), and G Protein-Coupled Receptor 30 (GPR30) in Testicular Tissue of Men with Klinefelter Syndrome.

Men with Klinefelter syndrome (KS) present severe hormonal dysregulation, particularly elevated serum estradiol concentration. Estrogens act through specific receptors and regulate testes development and spermatogenesis. Herein, we evaluated GPR30, ERα, and ERß mRNA expression in testis of KS men and men with 46XY karyotype by reverse transcriptase and quantitative PCR. ERß transcripts are the most abundant in testicular tissue of 46XY men. Notably, testicular GPR30 transcription in KS men was approximately 12 times higher. Since GPR30 is essential to mediate estrogen effects over steroidogenesis, our data illustrate that GPR30 may underpin the testicular alterations observed in KS men.

Novel Drug Therapies for Fertility Preservation in Men Undergoing Chemotherapy: Clinical Relevance of Protector Agents.

Cancer has been affecting a growing number of children, adolescents and adult males in reproductive age. Male reproductive potential is adversely affected by chemotherapeutic drugs and patients are at risk for prolonged infertility. Fertility recovery is related to the chemotherapeutic agent and dosage used, being thus difficult to predict. As a result, there is a strong need to identify a natural or synthetic compound that is able to preserve male fertility without interfering with the efficacy of the chemotherapeutic regimen. New procedures, as well as several drugs, are being investigated to assess their efficiency in protecting male reproductive functions from the chemotherapy side-effects. This review provides an overview of the wide range of chemotherapeutic drugs regularly used in cancer treatment and their detrimental effects on male fertility. In addition, it also assesses the existing protector agents for male fertility and their usefulness in preserving and protecting male reproductive functions exposed to chemotherapeutics. Several protector agents for male fertility are being studied, and results are promising. Nonetheless, further research must be implemented to identify a supplemental therapy that addresses the multiple side effects of chemotherapy on male reproductive function. Until such therapy is discovered, it is fundamental that all fertility preservation options are discussed with patients, before treatment is initiated, to assure parenthood.

Melatonin and male reproductive health: relevance of darkness and antioxidant properties.

The pineal hormone melatonin controls several physiological functions that reach far beyond the regulation of the circadian rhythm. Moreover, it can be produced in extra-pineal organs such as reproductive organs. The role of melatonin in the mammalian seasonal and circadian rhythm is well known. Nevertheless, its overall effect in male reproductive physiology remains largely unknown. Melatonin is a very powerful endogenous antioxidant that can also be exogenously taken safely. Interestingly, its antioxidant properties have been consistently reported to improve the male reproductive dysfunctions associated with pathological conditions and also with the exposure to toxicants. Nevertheless, the exact molecular mechanisms by which melatonin exerts its action in the male reproductive system remain a matter of debate. Herein, we propose to present an up-to-date overview of the melatonin effects in the male reproductive health and debate future directions to disclose possible sites of melatonin action in male reproductive system. We will discuss not only the role of melatonin during darkness and sleep but also the importance of the antioxidant properties of this hormone to male fertility. Since melatonin readily crosses the physiological barriers, such as the blood-testis barrier, and has a very low toxicity, it appears as an excellent candidate in the prevention and/or treatment of the multiple male reproductive dysfunctions associated with various pathologies.

Efeitos de diferentes tempos de extração no teor e composição química do óleo essencial de folhas de pariparoba [Pothomorphe umbellata (L. ) Miq. ] / Effects of time of extraction in the yield and chemical composition of the essential oil of pariparoba leaves [Pothomorphe umbellata (L. Miq. ]

O presente trabalho visou avaliar a influência de diferentes tempos de extração no teor e composição química do óleo essencial da espécie Pothomorphe umbellata. Folhas de pariparoba foram coletadas em Cajamar - SP, no mês de junho de 2006. O delineamento experimental adotado foi inteiramente casualizado, com seis tempos de extração (90, 120, 150, 180, 210 e 240 minutos) e 4 repetições. A extração do óleo essencial foi realizada por hidrodestilação e a análise química em CG-EM. O tempo de 180 minutos proporcionou maior rendimento do óleo essencial (0,42%), enquanto a composição química não foi influenciada pelos diferentes tempos de destilação. As principais substâncias identificadas foram: D-germacreno (65,5%), alfa-selineno (9,7%), trans-cariofileno (7,5%), e espatulenol (6,58%). Conclui-se que o tempo de extração afeta diretamente o rendimento e a proporção das substâncias químicas, recomendando-se a extração em até 180 minutos. .

The present work aimed to evaluate the influence of different times of extraction in the yield and chemical composition of the essential oil of "pariparoba" (Pothomorphe umbellate). Leaves of "pariparoba" were collected in the municipal district of Cajamar - state of São Paulo, Brazil, in June 2006. The adopted experimental design was completely randomized, with six times of extraction (90, 120, 150, 180, 210, and 240 minutes) and 4 repetitions. The extraction of the essential oil was accomplished by hydrodistillation, and the chemical analysis was performed in GC-MS. The time of extraction of 180 minutes provided greater yield of the essential oil (0.42%), and its chemical composition was not influenced by the different times of hydrodistillation. The main substances showed are D-germacrene (65.5%), alpha-selinene (9.7%), trans-caryophyllene (7.5%) and spathulenol (6.58%). The results of this work showed that the time of extraction affects the yield and the proportion of the chemical substances and it is recommended the extraction in up to 180 minutes.

High-energy diets: a threat for male fertility?

Male fertility is declining in developed countries, as well as in developing countries. External factors linked to lifestyle, such as eating disorders, negatively affect spermatogenesis, both at central and gonadal levels. The overconsumption of high-energy diets (HED) alters the functioning of the male reproductive axis and consequently affects the testicular physiology, disrupting its metabolism and bioenergetic capacity. Testicular metabolism presents unique characteristics, partly because of its cellular heterogeneity and to the specific functions that each cell type plays within the testicular environment. Disruption of the tightly regulated metabolic pathways leads to adverse reproductive outcomes, such as inefficient energy supply to germ cells, sperm defects or spermatogenesis arrest. Testicular metabolic alterations induced by HED intake may also lead to mitochondrial dysfunction, which is closely associated to reactive oxygen species (ROS) overproduction and oxidative stress. ROS easily target spermatozoa DNA and lipids, contributing to decreased sperm quality. Thus, understanding the detrimental effects of HED overconsumption on the pathways underlying testicular metabolism and sperm production is imperative; otherwise, one may favour a transgenerational amplification of subfertility. Herein, we present an up-to-date overview of the effects of HED on testicular metabolism, sperm parameters and the subsequent consequences for male fertility.

Mitochondrial quality control systems sustain brain mitochondrial bioenergetics in early stages of type 2 diabetes.

Mitochondria have a crucial role in the supply of energy to the brain. Mitochondrial alterations can lead to detrimental consequences on the function of brain cells and are thought to have a pivotal role in the pathogenesis of several neurologic disorders. This study was aimed to evaluate mitochondrial function, fusion-fission and biogenesis and autophagy in brain cortex of 6-month-old Goto-Kakizaki (GK) rats, an animal model of nonobese type 2 diabetes (T2D). No statistically significant alterations were observed in mitochondrial respiratory chain and oxidative phosphorylation system. A significant decrease in the protein levels of OPA1, a protein that facilitates mitochondrial fusion, was observed in brain cortex of GK rats. Furthermore, a significant decrease in the protein levels of LC3-II and a significant increase in protein levels of mTOR phosphorylated at serine residue 2448 were observed in GK rats suggesting a suppression of autophagy in diabetic brain cortex. No significant alterations were observed in the parameters related to mitochondrial biogenesis. Altogether, these results demonstrate that during the early stages of T2D, brain mitochondrial function is maintained in part due to a delicate balance between mitochondrial fusion-fission and biogenesis and autophagy. However, future studies are warranted to evaluate the role of mitochondrial quality control pathways in late stages of T2D.

Insulin therapy modulates mitochondrial dynamics and biogenesis, autophagy and tau protein phosphorylation in the brain of type 1 diabetic rats.

The main purpose of this study was to examine whether streptozotocin (STZ)-induced type 1 diabetes (T1D) and insulin (INS) treatment affect mitochondrial function, fission/fusion and biogenesis, autophagy and tau protein phosphorylation in cerebral cortex from diabetic rats treated or not with INS. No significant alterations were observed in mitochondrial function as well as pyruvate levels, despite the significant increase in glucose levels observed in INS-treated diabetic rats. A significant increase in DRP1 protein phosphorylated at Ser616 residue was observed in the brain cortex of STZ rats. Also an increase in NRF2 protein levels and in the number of copies of mtDNA were observed in STZ diabetic rats, these alterations being normalized by INS. A slight decrease in LC3-II levels was observed in INS-treated rats when compared to STZ diabetic animals. An increase in tau protein phosphorylation at Ser396 residue was observed in STZ diabetic rats while INS treatment partially reversed that effect. Accordingly, a modest reduction in the activation of GSK3ß and a significant increase in the activity of phosphatase 2A were found in INS-treated rats when compared to STZ diabetic animals. No significant alterations were observed in caspases 9 and 3 activity and synaptophysin and PSD95 levels. Altogether our results show that mitochondrial alterations induced by T1D seem to involve compensation mechanisms since no significant changes in mitochondrial function and synaptic integrity were observed in diabetic animals. In addition, INS treatment is able to normalize the alterations induced by T1D supporting the importance of INS signaling in the brain.

Transgenic overexpression of regucalcin leads to suppression of thapsigargin- and actinomycin D-induced apoptosis in the testis by modulation of apoptotic pathways.

Recent evidence suggested the involvement of calcium-binding protein regucalcin (RGN) in testicular apoptosis. Herein, we investigated the role of RGN controlling apoptotic pathways in the testis by using a transgenic rat model overexpressing RGN (Tg-RGN). Seminiferous tubules (SeT) from Tg-RGN and their wild-type (Wt) counterparts were cultured ex vivo in presence or absence of apoptosis inducers thapsigargin (Thap, 10(-7) and 10(-6) m) and actinomycin D (Act D, 0.5 and 1 µg/mL). Expression levels of key regulators of apoptosis in SeT of Tg-RGN and Wt animals were determined by quantitative real-time PCR and Western blot analysis. Measurement of caspase-3 enzymatic activity was included as an end point of apoptosis. Tg-RGN SeT treated with 10(-6) m of Thap or 1 µg/mL of Act D showed a diminished enzymatic activity and gene transcription of caspase-3, along with increased mRNA and protein expression of antiapoptotic Bcl-2. Bcl-2/Bax (antiapoptotic/proapoptotic) protein ratio was also enhanced in these SeT. Although caspase-9 mRNA was increased in the SeT of Tg-RGN treated with Thap, no differences were observed at protein level, and no differences were also found on protein levels of apoptosis-inducing factor. mRNA expression of proapoptotic p53 and p21 was strongly decreased in Tg-RGN SeT treated with Thap (10(-6) m) or Act D (1 µg/mL). These findings demonstrated that RGN suppresses Thap- and Act D-induced apoptosis in SeT by modulating the expression and activity of key apoptotic and antiapoptotic factors. Moreover, results indicate that RGN overexpression protects germ cell from apoptosis induced by noxious stimuli, which could be a relevant mechanism for fertility preservation in situations of oncological treatments.

Metformin and male reproduction: effects on Sertoli cell metabolism.

BACKGROUND AND PURPOSE: Metformin is commonly used to treat type 2 diabetes (T2D). While new clinical applications have been ascribed to metformin, including treatment of anovulatory infertility, its effects on male reproduction have not been investigated. The Sertoli cell (SC) is crucial for germ cell development, exerting metabolic control of spermatogenesis, therefore, we investigated the effects of metformin on SC metabolism. EXPERIMENTAL APPROACH: Rat SCs were cultured in the absence and presence of metformin (5, 50 and 500 µM). mRNA and protein levels of glucose transporters (GLUT1 and GLUT3), phosphofructokinase 1 (PFK 1), lactate dehydrogenase (LDH) and monocarboxylate transporter 4 (MCT4) were determined by quantitative PCR and Western blot respectively. LDH activity was assessed and metabolite production/consumption determined by (1) H-NMR. KEY RESULTS: Metformin (50 µM) decreased mRNA and protein levels of GLUT1, GLUT3, MCT4 and PFK 1 but did not affect LDH mRNA or protein levels. However, although glucose consumption was maintained in metformin-treated cells, LDH activity, lactate and alanine production were increased, indicating an enhanced glycolytic flux. No metabolic cytotoxicity was detected in SCs exposed to supra-pharmacological concentration of metformin. CONCLUSIONS AND IMPLICATIONS: Our results indicate that metformin: (i) decreases mRNA and protein levels of glycolysis-related transporters in SCs but increases their activity; and (ii) stimulates alanine production, which induces antioxidant activity and maintains the NADH/NAD(+) equilibrium. The increased lactate in metformin-treated SCs provides nutritional support and has an anti-apoptotic effect in developing germ cells. Thus, metformin can be considered as a suitable antidiabetic drug for male patients of reproductive age with T2D.