Impaired hypothalamic-pituitary-gonadal axis function in men with diabetes mellitus

Kiwifruit (Actinidia deliciosa) aqueous extract improves hyperglycemia, testicular inflammation, apoptosis, and tissue structure induced by Streptozotocin via oxidative stress inhibition

Diabetes mellitus (DM) is a well-known hyperglycemic metabolic condition identified by oxidative stress and biological function disruption. Kiwifruit is a valuable source of polyphenols and vitamin C with great antioxidant, nutritional, and health-promoting effects. Therefore, this study was initiated to explore the antioxidant and anti-hyperglycemic effects of kiwifruit aqueous extract (KFE) against oxidative injury and testis dysfunction in rats with diabetes. Twenty-four male Wistar Albino rats (160-170 g) were divided into four groups: Group 1 served as the control, Group 2 supplemented orally with kiwifruit extract (KFE; 1 g/kg/day) for one month, Group 3 was treated with a single streptozotocin dose (STZ; 50 mg/kg ip), and Group 4 where the diabetic rats were administered with KFE, respectively. According to the results, the GC-MS analysis of KFE revealed several main components with strong antioxidant properties. In diabetic rats, lipid peroxidation and hyperglycemia were accompanied by perturbations in hormone levels and sperm characteristics. Antioxidant enzymes, glutathione content, aminotransferase, phosphatase activities, and protein content were decreased. Furthermore, histology, immunohistochemical PCNA expression, and histochemical analysis of collagen, DNA, RNA, and total protein. were altered in rat testis sections, supporting the changes in biochemistry. Furthermore, diabetic rats supplemented with KFE manifested considerable amendment in all the tested parameters besides improved tissue structure and gene expressions (NF-kB, p53, IL-1β, Bax, IL-10, and Bcl2) relative to the diabetic group. In conclusion, KFE has beneficial effects as it can improve glucose levels and testis function, so it might be used as a complementary therapy in DM.

Withaferin-A attenuates diabetes mellitus induced male reproductive dysfunction mediated by ERα in brain and testes of Swiss albino mice

Diabetes mellitus (DM) is a chronic metabolic disease, characterized by persistent hyperglycemia resulting from diminished insulin secretion or insulin resistance. The present study evaluated the ameliorative effects of Withaferin-A (WA) on DM-induced reproductive dysfunction in mice. For the same, mice were intraperitoneally injected with Streptozotocin (STZ), (40 mg/kg/day) for 5 consecutive days to induce DM. Mice were then treated with WA (8 mg/kg/day) in normal and diabetic conditions (STZ + WA). Next, blood glucose levels, oral glucose tolerance, intraperitoneal insulin tolerance, oxidative stress and reproductive parameters were estimated. For reproductive performance, immunofluorescent localization of gonadotropin-releasing hormone (GnRH-I) and estrogen receptor alpha (ERα) in the preoptic area and paraventricular nucleus region of hypothalamus and ERα in testes was performed. STZ-induced diabetes triggered reproductive dysfunctions as mediated by low GnRH-I and ERα in the brain and ERα in the testes along with declined testosterone and estradiol levels. Treatment with WA significantly reduced the blood glucose levels and enhanced glucose clearance accompanied by reduced oxidative stress in the brain, pancreas and testes as indicated by the low levels of H2O2 and MDA in diabetic mice treated with WA (STZ + WA). This study reports, for the first time, that WA can efficiently ameliorate DM-induced reproductive dysfunctions by enhancing endogenous testosterone, estrogen and increased GnRH-I and ERα in the brain and ERα in the testes of DM-induced male mice.

Role of sex hormones in diabetic nephropathy

Diabetic nephropathy (DN) is the most common microvascular complication in diabetes and one of the leading causes of end-stage renal disease. The standard treatments for patients with classic DN focus on blood glucose and blood pressure control, but these treatments can only slow the progression of DN instead of stopping or reversing the disease. In recent years, new drugs targeting the pathological mechanisms of DN (e.g., blocking oxidative stress or inflammation) have emerged, and new therapeutic strategies targeting pathological mechanisms are gaining increasing attention. A growing number of epidemiological and clinical studies suggest that sex hormones play an important role in the onset and progression of DN. Testosterone is the main sex hormone in males and is thought to accelerate the occurrence and progression of DN. Estrogen is the main sex hormone in females and is thought to have renoprotective effects. However, the underlying molecular mechanism by which sex hormones regulate DN has not been fully elucidated and summarized. This review aims to summarize the correlation between sex hormones and DN and evaluate the value of hormonotherapy in DN.

Diabetes Type 1 Negatively Influences Leydig Cell Function in Rats, Which is Partially Reversible By Insulin Treatment

Type 1 diabetes mellitus (T1DM) is associated with impaired spermatogenesis and lower testosterone levels and epididymal weight. However, the underlying processes in the testis are unknown and remain to be elucidated. Therefore, the present study focused on the effects of T1DM on testicular function in a spontaneously diabetic rat model. BB/OKL rats after diabetes manifestation were divided into 3 groups: those without insulin treatment and insulin treatment for a duration of 2 and of 6 weeks. Anthropometrical data, circulating levels of gonadotrophins, testosterone, and inhibin B were measured. Intratesticular testosterone, oxidative stress, inflammation, and apoptosis were analyzed. Key enzymes of steroidogenesis were evaluated in the testis. Untreated diabetic rats had significantly lower serum follicle-stimulating hormone and luteinizing hormone levels. Serum and intratesticular testosterone levels significantly decreased in untreated diabetic rats compared to healthy controls. Key markers of Leydig cell function were significantly downregulated at the RNA level: insulin-like factor 3 (Insl3) by 53% (P = .006), Star by 51% (P = .004), Cyp11A1 by 80% (P = .003), 3Beta-Hsd2 by 61% (P = .005), and Pbr by 52% (P = .002). In the insulin-treated group, only Cyp11A1 and 3Beta-Hsd2 transcripts were significantly lower. Interestingly, the long-term insulin-treated group showed significant upregulation of most steroidogenic enzymes without affecting testosterone levels. Tumor necrosis factor α and apoptosis were significantly increased in the long-term insulin-treated rats. In conclusion T1DM, with a severe lack of insulin, has an adverse action on Leydig cell function. This is partially reversible with well-compensated blood glucose control. Long-term T1DM adversely affects Leydig cell function because of the process of inflammation and apoptosis.

Momordica cymbalaria improves reproductive parameters in alloxan-induced male diabetic rats

Male reproductive dysfunction is one of the common complications of diabetes mellitus that causes infertility. This study was designed to investigate the protective effect of Momordica cymbalaria (M. cymbalaria) extracts on diabetes mediated reproductive toxicity in male Wistar rats. The induction of diabetes was performed using a single intraperitoneal injection of alloxan (120 mg/kg). Skin and seed extracts (250 and 500 mg/kg) of M. cymbalaria were orally administered to alloxan-induced diabetic male rats for 28 days. Postprandial blood glucose (PBG) levels were recorded at 7-day interval for four weeks. The effects of the treatment on blood glucose, weight of reproductive organs, sperm count, testosterone levels, antioxidant capacity, and histomorphology were evaluated. Treatment with the above extracts of M. cymbalaria significantly (p < 0.05) improved the reproductive parameters as well as the antioxidant levels superoxide dismutase (SOD) and glutathione-s-transferase (GST) in the diabetic rats. Also, oral treatment with M. cymbalaria extracts significantly reduced the PBG and malondialdehyde (MDA) levels. Further, it revived the histomorphology of reproductive organs in diabetic rats. Interestingly, skin extract at a dose of 500 mg/kg was found to be more efficient in elevating the level of testosterone and sperm count in the diabetic rats. Based on the results, it is clear that M. cymbalaria not only regulates the postprandial blood glucose levels but also improves the reproductive health in the diabetic state.

The Effect of Rooibos (Aspalathus linearis), Honeybush (Cyclopia intermedia) and Sutherlandia (Lessertia frutescens) on Testicular Insulin Signalling in Streptozotocin-Induced Diabetes in Wistar Rats

BACKGROUND

Testicular insulin signalling is altered in diabetic (DM) males. While unravelling the mechanism through which DM exert these detrimental effects, studies have shown the importance of insulin regulation in glucose homeostasis, and how a lack in insulin secretion indirectly led to reduced male fertility. The current study aimed to investigate the role of rooibos, honeybush and Sutherlandia on insulin signalling in the testicular tissue of type I diabetic rats.

METHODS

Animals (n=60) were randomly divided into six groups. The groups include a control group, a vehicle group, and diabetes was induced in the remainder of animals via a single intraperitoneal injection of STZ at 45mg/kg. The remaining four groups included a diabetic control (DC), diabetic + rooibos (DRF), diabetic + honeybush (DHB) and diabetic + Sutherlandia group (DSL). Animals were sacrificed after seven weeks of treatment, and blood and testes were collected.

RESULTS

All diabetic groups (DC, DRF, DHB, DSL) presented with a significant increase in blood glucose levels after diabetes induction compared to the control and vehicle (p<0.001). The DC animals presented with decreased testicular protein expression of IRS-1, PkB/Akt and GLUT4 compared to controls. DRF and DHB animals displayed an acute upregulation in IRS-1, while the DSL group showed improvement in IRS-2 compared to DC. Although, DRF animals presented with a decrease in PkB/Akt, DHB and DSL animals displayed upregulation (22.3%, 48%) compared to controls, respectively.

CONCLUSION

The results taken together, it can be suggested that these infusions may enhance insulin signalling through diverse pathways.

Diabetes mellitus and the impairment of male reproductive function: Possible signaling pathways

BACKGROUND AND AIMS

Today, it has been shown that diabetes mellitus (DM) can affect male fertility. Glucose metabolism is a vital process in spermatogenesis that is impacted by diabetes condition. But the mechanisms by which DM causes male infertility are not wholly clarified. The aim of this review is to provide brief information about the influence of hyperglycemia on male fertility and specific emphasis on the molecular signaling pathway that is involved.

METHODS

Broad literature search in the electronic database "Pubmed", "Google Scholar", the website of "World Health Organization" (WHO) and Control Disease and Prevention (CDC) took place. There was no time restriction. A key criterion for the selection of articles was English and language. Finally, one hundred thirty seven articles were included in the review.

RESULTS

Diabetes mellitus affects many signaling pathways that involved in the spermatogenesis. It seems that increased ROS and oxidative stress in the diabetes is the beginning of all fertility problems and affects all of involved signaling pathways in the spermatogenesis.

CONCLUSIONS

It seems that there was strong interconnected between oxidative stress and all of involved signaling pathways in the reproductive problems in diabetes. So, approaches that diminish oxidative stress in the testis can be effective in improving diabetes related infertility complications.

Effects of testicular sperm aspiration upon first cycle ICSI-ET for type 2 diabetic male patients

Male diabetes mellitus (DM) can affect erectile function and sperm quality. In severe cases, DM can lead to retrograde or no ejaculation, so testicular sperm aspiration (TESA) is combined with intracytoplasmic sperm injection (ICSI) to treat subfertility and infertility for DM couples. However, the effect of TESA upon ICSI (TESA-ICSI) for DM patients remains unclear. This research investigated the effect of TESA-ICSI on first cycle ICSI-embryo transfer (ICSI-ET) for type 2 diabetic mellitus (T2DM) patients and the potential mechanisms. The subjects consisted of 1219 male patients with azoospermia or retrograde ejaculation who were treated with TESA-ICSI from 2015.01 to 2019.11. They were classified into two groups, the T2DM group (n = 54) and non-diabetic control group (n = 1165). Sperm selection for injection was performed using motile sperm organelle morphology examination criteria. The number of available embryos and the high-quality embryo rates following a single ET as well as cleavage, fertilization, implantation, clinical pregnancy and the abortion rates were noted. Compared with the non-diabetic group, the available embryo rate (75.20 ± 26.40% vs.78.36 ± 23.25%) and high-quality embryo rate (46.49 ± 30.37% vs. 47.55 ± 28.57%) in the T2DM group were lower and the abortion rate (20.83% vs. 8.88%) was higher, but these differences were not statistically significant. There were no significant differences in clinical pregnancy, implantation, normal fertilization, and cleavage rates between the two groups. The results show that TESA for male T2DM patients does not influence the effect of ICSI. For T2DM patients with severe oligozoospermia, asthenospermia, teratozoospermia, or retrograde ejaculation that do not meet ICSI criteria, TESA-ICSI may perhaps be considered for reproductive assistance.

ABBREVIATIONS

DM: diabetes mellitus; TESA: testicular sperm aspiration; ICSI: intracytoplasmic sperm injection; ICSI-ET; ICSI-embryo transfer; LH: luteinizing hormone; mL: milliliter; TES: testosterone; FSH: follicle-stimulating hormone; P: progesterone; HCG: human chorionic gonadotropin.

The effect of dietary protein intake on factors associated with male infertility: A systematic literature review and meta-analysis of animal clinical trials in rats

BACKGROUND

Studies have shown that the amount of protein in the diet affects the hypothalamic-pituitary-testis axis and sub-optimal quantity reduces male fertility potential in both animals and humans. However, individual research reports on the factors associated with male infertility are collectively uncharacterized.

AIM

We systematically reviewed, and meta-analysed animal (rats) studies on the effect of low protein diet on factors associated with male infertility.

METHODS

PubMed Central, EMBASE and Scopus databases were searched from inception to 30 March 2019 for the study concepts and related keywords in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. Data on the outcome measures were extracted and pooled across trials using random-effects model and expressed as mean differences (MD) at a 95% confidence interval (CI).

RESULTS

Twelve trials identified from 3327 studies, met our inclusion criteria in the comparison of a low protein diet (2-10% protein) vs control protein diet (17-23% protein). The results showed that a low protein diet caused a significant reduction in the body weight (P = 0.0001) testis weight (P = 0.0001), seminal vesicle weight (P = 0.0003), epididymis weight P = 0.02), serum testosterone (P = 0.001) and follicle-stimulating hormone (FSH) concentrations (P = 0.04) compared with the control treatments. No effect on luteinizing hormone (LH) plasma concentration (P = 0.13) was observed.

CONCLUSION

This study revealed that low protein diet caused significant reductions in body weight, testis, epididymis and seminal vesicle weights, serum testosterone and FSH concentration in rats. We infer that sub-optimal protein consumption reduces the gonadal and endocrine function, and consequently male infertility.

Effects of Myricitrin and Solid Lipid Nanoparticle-Containing Myricitrin on Reproductive System Disorders Induced by Diabetes in Male Mouse

Purpose

The present study investigates the effects of myricitrin and solid lipid nanoparticle (SLN) containing myricitrin on the reproductive system of type 2 diabetic male mice.

Materials and Methods

In this experimental study, SLN containing myricitrin was prepared by the cold homogenization method. Then, 90 adult male Naval Medical Research Institute mice were divided into 9 groups (n=10): control, vehicle, diabetic, diabetic+myricitrin or SLN containing myricitrin 1, 3, and 10 mg/kg. Diabetes was induced by streptozotocin (65 mg/kg) 15 minutes after nicotinamide (120 mg/kg) injection. Myricitrin and SLN containing myricitrin administered during 1 month. At the 34th days of the experiment, plasma and tissue samples were taken for experimental assessments.

Results

Testis weight and volume decreased in the diabetic group. These variables increased in diabetic treated mice by a high dose of myricitrin or all doses of SLN containing myricitrin (p<0.05). Total antioxidant capacity and superoxide dismutase levels decreased in diabetic mice, and administration of myricitrin 10 mg/kg or all doses of SLN containing myricitrin increased them (p<0.05). Luteinizing hormone, Follicle-stimulating hormone, testosterone, and sperm count decreased in the diabetic group, treatment with a high dose of myricitrin or all doses of SLN containing myricitrin recovered them (p<0.05). Diabetes induced vacuoles and apoptosis in testicular cells, meanwhile myricitrin and SLN containing myricitrin improved them (p<0.05).

Conclusions

Diabetes induced reproductive problem via increased oxidative stress and decrease antioxidant capacity, administration of myricitrin or SLN containing myricitrin improved them. Further, SLN containing myricitrin was more potent than myricitrin.

Hyperglycemia induces spermatogenic disruption via major pathways of diabetes pathogenesis

Diabetes-induced hyperglycemia has previously been shown to impact on male sub-/infertility, however, still little is known about the underlying mechanisms. In the present study we have addressed three major biochemical pathways implicated in the pathogenesis of hyperglycemia induced organ damage (the advanced glycation end product (AGE) formation pathway, the diacylglycerol-protein kinase C pathway (PKC), and the polyol pathway) in both testis and epididymis of the Ins2^Akita mouse model of Type 1 diabetes (T1DM). Hyperglycemia activated both the PKC and the polyol pathway in a significant and progressive manner within the testis, but not within the epididymis. While the AGE receptor was ubiquitiously expressed in the testis, concentrations of precursor methylglyoxal and AGE carboxymethyllysine were increased in both epididymis and testis in diabetic mice. However, AGEs did not activate intracellular pathways of ERK1, ERK2, Rela, Nrf-2, IkBkB, NFkB except CDC42, Akt1. In conclusion, two of the major pathways of hyperglycemia-induced organ damage were clearly activated within the testis of T1DM mice. This provides therapeutical opportunities in the treatment of diabetic male reproductive dysfunction.

Lower circulating kisspeptin and primary hypogonadism in men with type 2 diabetes

Introduction

Kisspeptin influence on male androgens is partially understood. We aimed to evaluate serum concentrations of kisspeptin among Ghanaian men with type 2 diabetes and to identify related factors that may contribute to altering circulating kisspeptin.

Methods

A cross‐sectional, observational study. Sixty persons with type 2 diabetes and 60 nondiabetic controls were included in this study. Blood pressure, body mass index (BMI), kisspeptin, luteinizing hormone (LH), follicle‐stimulating hormone (FSH), total testosterone (T), glucose (FBG), glycated haemoglobin (HbA1c) and lipid levels were assessed.

Results

Type 2 diabetic men had lower kisspeptin and T concentrations than controls (P = 0.001 for both). Levels of LH and FSH were, respectively, higher in diabetic men compared with their control counterparts (P = 0.003; P = 0.017). There were negative associations within the diabetic group for kisspeptin vs age (r = −0.590, P = 0.0001) and kisspeptin vs BMI (r = −0.389, P = 0.002). Positive associations were also found within the diabetic group for kisspeptin vs T (r = 0.531, P = 0.001), kisspeptin vs LH (r = 0.423, P = 0.001) and kisspeptin vs FSH (r = 0.366, P = 0.004). Lower T (OR = 1.473, P = 0.003) and advancing age (OR = 0.890, P = 0.004) contributed to decreased kisspeptin levels among Ghanaian males with type 2 diabetes.

Conclusion

Our data demonstrate that circulating kisspeptin and T concentrations are lower among men with type 2 diabetes and highlight the importance of considering kisspeptin concentrations in the management of hypogonadism and type 2 diabetes.

Vitexin alleviates streptozotocin-induced sexual dysfunction and fertility impairments in male mice via modulating the hypothalamus-pituitary-gonadal axis

Diabetes-associated sexual dysfunction and fertility impairments are major secondary complications in diabetic patients and animal models. Natural herbs are important sources of therapeutic agents for diabetic complications. This study investigated the effect of vitexin on male sexual dysfunction and fertility impairments in streptozotocin (STZ)-induced diabetic mice. Diabetes was induced by intraperitoneal injection of 45 mg/kg STZ for 5 consecutive days in mice. Vitexin (10, 20 or 40 mg/kg) and Sildenafil citrate (SC, 5 mg/kg) were administered daily for 62 days after the induction of diabetes. The parameters of sexual behavior and fertility were analyzed. The reproductive organ weight, sperm motility, and viability of the treated mice were examined. Testicular histopathological alterations were detected by hematoxylin and eosin (H&E) staining. Enzyme-linked immunosorbent assay (ELISA) was used to evaluate serum hormonal levels. Results showed that 40 mg/kg vitexin significantly improved the sexual behavior and fertility levels compared with the diabetic group. Moreover, vitexin (20 or 40 mg/kg) significantly increased reproductive organ weight and improved testicular pathological structure damage. Meanwhile, sperm analysis demonstrated that vitexin significantly restored sperm quality in a dose-dependent manner. Furthermore, ELISA data showed that vitexin significantly increased the serum testosterone (T), follicular-stimulating hormone (FSH), and luteinizing hormone (LH) levels but decreased the gonadotropin-releasing hormone (GnRH) level to different degrees. These findings suggest that vitexin ameliorates sexual dysfunction and fertility impairments in male diabetic mice possibly by modulating the hypothalamus-pituitary-gonadal axis.

The effect of metabolic syndrome on male reproductive health: A cross-sectional study in a group of fertile men and male partners of infertile couples

This study aimed to determine the effect of metabolic syndrome (MS) on the reproductive function in fertile (FM) and male partners of infertile couples (MPIC). We performed a cross-sectional study formatting two study groups: partners of pregnant women (n = 238; mean age 32.0) as FM and male partners of infertile couples (n = 2642; mean age 32.6) as MPIC. A standard semen analysis was performed and clinical, laboratory and lifestyle data were analysed. The adapted NCEP-ATPIII criteria were used to define MS. 12.2% of FM and 17.8% of MPIC had MS. In both groups, men with MS were older, they were centrally obese and had higher triglycerides, systolic and diastolic blood pressure and decreased HDL cholesterol values as compared to men without MS. However, glucose concentrations as well as fasting insulin levels were significantly higher only in the MPIC-MS⁺ group. MS was not associated with semen parameters. Testosterone levels were negatively correlated to MS in both groups. This negative association persisted within the BMI categories between MPIC-MS^- and MPIC-MS⁺ groups. LH was negatively correlated to MS but only in MPIC. FSH and oestradiol were not correlated to MS. Smoking and alcohol consumption were higher among men with MS. This study shows that except for testosterone, MS has no independent effect on major fertility parameters in different subgroups of men.

Hyperglycemia is associated with reduced testicular function and activin dysregulation in the Ins2Akita+/- mouse model of type 1 diabetes

Type 1 diabetes (T1D) is associated with subfertility in men. We hypothesised that this results from inhibitory effects of chronic hyperglycemia on testicular function and used the Ins2^Akita+/- mouse model to investigate this. Diabetic mice exhibited progressive testicular dysfunction, with a 30% reduction in testis weight at 24 weeks of age. Diabetic mice showed significantly reduced seminiferous tubule diameters and increased spermatogenic disruption, although testes morphology appeared grossly normal. Unexpectedly, serum LH and intra-testicular testosterone were similar in all groups. Ins2^Akita+/- mice displayed elevation of the testicular inflammatory cytokines activin A and IL-6. Intratesticular activin B was downregulated, while the activin regulatory proteins, follistatin and inhibin, were unchanged. Activin signalling, measured by pSmad3 and Smad4 production, was enhanced in diabetic mice only. These results suggest that prolonged exposure to hyperglycemia in the Ins2^Akita+/- mice leads to progressive testicular disruption mediated by testicular activin activity, rather than hormonal dysregulation.

Testicular Metabolic Reprogramming in Neonatal Streptozotocin-Induced Type 2 Diabetic Rats Impairs Glycolytic Flux and Promotes Glycogen Synthesis

Defects in testicular metabolism are directly implicated with male infertility, but most of the mechanisms associated with type 2 diabetes- (T2DM) induced male infertility remain unknown. We aimed to evaluate the effects of T2DM on testicular glucose metabolism by using a neonatal-streptozotocin- (n-STZ) T2DM animal model. Plasma and testicular hormonal levels were evaluated using specific kits. mRNA and protein expression levels were assessed by real-time PCR and Western Blot, respectively. Testicular metabolic profile was assessed by (1)H-NMR spectroscopy. T2DM rats showed increased glycemic levels, impaired glucose tolerance and hyperinsulinemia. Both testicular and serum testosterone levels were decreased, whereas those of 17β-estradiol were not altered. Testicular glycolytic flux was not favored in testicles of T2DM rats, since, despite the increased expression of both glucose transporters 1 and 3 and the enzyme phosphofructokinase 1, lactate dehydrogenase activity was severely decreased contributing to lower testicular lactate content. However, T2DM enhanced testicular glycogen accumulation, by modulating the availability of the precursors for its synthesis. T2DM also affected the reproductive sperm parameters. Taken together these results indicate that T2DM is able to reprogram testicular metabolism by enhancing alternative metabolic pathways, particularly glycogen synthesis, and such alterations are associated with impaired sperm parameters.

High-energy diets may induce a pre-diabetic state altering testicular glycolytic metabolic profile and male reproductive parameters

Diabetes mellitus is a metabolic disorder that may arise from diet habits and is growing to epidemic proportions. Young male diabetic patients present high infertility/subfertility prevalence resulting from impaired reproductive function and poor semen quality. We aimed to evaluate the effects of a high-energy diet (HED) on glucose tolerance/insulin levels and correlate the observed effects on male reproductive function with overall testicular metabolism. After 1 month, HED fed rats showed increased glycaemic levels, impaired glucose tolerance and hypoinsulinaemia. Moreover, an imbalance of intratesticular and serum testosterone levels was observed, whereas those of 17β-estradiol were not altered. High-energy diet also affected the reproductive parameters, with HED rats exhibiting a significant increase in abnormal sperm morphology. Glycolytic metabolism was favoured in testicles of HED rats with an increased expression of both glucose transporters 1 (GLUT1) and 3 (GLUT3) and the enzyme phosphofrutokinase 1. Moreover, lactate production and the expression of metabolism-associated genes and proteins involved in lactate production and transport were also enhanced by HED. Alanine testicular content was decreased and thus intratesticular lactate/alanine ratio in HED rats was increased, suggesting increased oxidative stress. Other energetic substrates such as acetate and creatine were not altered in testis from HED rats, but intratesticular glycine content was increased in those animals. Taken together, these results suggest that HED induces a pre-diabetic state that may impair reproductive function by modulating overall testicular metabolism. This is the first report on testicular metabolic features and mechanisms related with the onset of a pre-diabetic state.

The effects of type 1 diabetes on the hypothalamic, pituitary and testes axis

Type 1 diabetes is an autoimmune disorder characterized by a lack of insulin production by the beta cells of the pancreas. This lack of insulin causes a variety of systemic effects on whole-body metabolism. Poorly managed type 1 diabetes can lead to cardiovascular disease, diabetic neuropathy, and diabetic retinopathy. Increasingly, even well-managed type 1 diabetic patients show damage to peripheral organs related to complications from the disease. The central role of insulin in energy homeostasis also renders it an important signaling factor in the reproductive tract. type 1 diabetes has now been demonstrated to cause defects in sperm and testes. The aim of this review is to present the known effects of insulin's role in the function of the male reproductive tract. These effects might be mediated through hormonal alterations in the hypothalamic pituitary gonadal axis or through the direct interaction of insulin on the testes and sperm cells. Although fertility complications also occur in type 2 diabetic males, this review will focus on the defects specifically linked with the lack of insulin seen in type 1 diabetes.

Excessive dietary calcium in the disruption of structural and functional status of adult male reproductive system in rat with possible mechanism

Calcium is essential for functioning of different systems including male reproduction. However, it has also been reported as chemo-castrative agent. The study has been undertaken to elucidate the effect of excessive dietary calcium on male reproductive system in animals with possible action. Adult male healthy rats fed CaCl(2) at different doses (0.5, 1.0 and 1.5 g%) in diet for 13 and 26 days to investigate reproductive parameters as well as the markers of oxidative stress. Significant alteration was found (P < 0.05) in testicular and accessory sex organs weight, epididymal sperm count, testicular steroidogenic enzyme (Δ(5) 3β-HSD and 17β-HSD) activities, serum testosterone, LH, FSH, LPO, activities of antioxidant enzymes, testicular histoarchitecture along with adrenal Δ(5) 3β-HSD activity with corticosterone level in dose- and time-dependent manner. Overall observations suggest that excessive dietary calcium enhances the generation of free-radicals resulting in structural and functional disruption of male reproduction.

Protection of testicular dysfunctions by MTEC, a formulated herbal drug, in streptozotocin induced diabetic rat

Single injection of streptozotocin (STZ) resulted diabetes mellitus which was reflected here by the levels of fasting blood glucose and serum insulin. Moreover, this experimental diabetes also resulted testicular dysfunctions evaluated by count, viability and motility of sperm as well as by the activities of key enzymes for androgen synthesis. Diabetes induced testicular oxidative stress has been indicated here by the monitoring of testicular peroxidase and catalase activities as well as by quantification of TBARS and CD of testis. Testicular glucose was increased and leydig cell nuclear area was decreased in STZ induced diabetes. Treatment of herbal formulated drug named as MTEC consist of aqueous-methanol extract of Musa paradisiaca, Tamarindus indica, Eugenia jambolana and Coccinia indica to streptozotocin induced diabetic rat at the ratio of 2:2:1:1 at the dose of 60 mg/d for two times a day for 14 d resulted a significant protection in fasting blood glucose and serum insulin levels (p<0.05) along with correction of testicular above parameters towards the control level (p<0.05). This herbal formulated drug has no general toxic effects on the body weight, as well as on the activities of serum glutamate and pyruvate transaminases in serum. The results support the validity of this herbal drug for the management of testicular disorders noted in diabetic state.

Role of reactive oxygen species and antioxidants on pathophysiology of male reproduction

The excessive generation of reactive oxygen species (ROS) by abnormal spermatozoa and contaminating leukocytes has been defined as one of the few etiologies for male infertility. Administration of antioxidants in patients with 'male factor' infertility has begun to attract considerable interest. The main difficulty of such an approach is our incomplete understanding of the role of free radicals in normal and abnormal sperm function leading to male infertility. Mammalian spermatozoa membranes are very sensitive to free radical induced damage mediated by lipid peroxidation, as they are rich in polyunsaturated fatty acids. Limited endogenous mechanisms exist to reverse these damages. ROS attacks the fluidity of the sperm plasma membrane and the integrity of DNA in the sperm nucleus. ROS induced DNA damage accelerate the germ cell apoptosis. Unfortunately spermatozoa are unable to repair the damage induced by excessive ROS as they lack the cytoplasmic enzymes required to accomplish the repair. Assessment of such oxidative stress status (OSS) may help in the medical treatment. Treatment strategies must be directed toward lowering of ROS levels to keep only a small amount necessary to maintain normal cell function.