Testicular function and glycemic control in diabetic men. A controlled study

New perspectives in functional hypogonadotropic hypogonadism: beyond late onset hypogonadism

Functional hypogonadotropic hypogonadism (FHH) is an increasingly frequent condition, whose pathological mechanisms are not yet fully clarified. The concept of FHH has now completely replaced that of late onset hypogonadism, that only concerned the ageing man. FHH is the result of an impairment of the hypothalamic-pituitary gonadal axis (HPG-A) function, resulting in decreased testosterone concentrations associated with low or inappropriately normal gonadotropin levels and infertility; it can be diagnosed once organic causes of hypogonadism are excluded. The growing occurrence of FHH derives from its association with widespread conditions, such as obesity and diabetes mellitus, but also to the increasing ease and frequency of use of several drugs, such as opioids, glucocorticoids, and sex steroids. Moreover, given the tendency of many subjects to excessive physical activity and drastic reduction in caloric intake, FHH may also be secondary to low energy availability. Finally, the association with HIV infection should not be overlooked. Therefore, there is an important variability in the diseases that can lead to FHH. Despite the heterogeneity of the underlying pathologies, the mechanisms leading to FHH would seem quite similar, with the initial event represented by the impairment at the HPG-A level. Nevertheless, many different biological pathways are involved in the pathogenesis of FHH, therefore the aim of the current paper is to provide an overview of the main relevant mechanisms, through a detailed analysis of the literature, focusing specifically on pathogenesis and clinical, diagnostic and therapeutic aspects.

Effects of diabetes mellitus on sperm quality and fertility outcomes: Clinical evidence

BACKGROUND

Diabetes mellitus is a global epidemic characterized by high morbidity and mortality. Diabetes mellitus can lead to acute and chronic systemic complications. Among them, a negative effect of diabetes mellitus on sperm quality and male/couple fertility has been suggested. However, available studies in diabetes mellitus men evaluated relatively small cohorts with discordant results.

OBJECTIVES

To evaluate the clinical evidences of the effects of diabetes mellitus on sperm quality and fertility outcomes.

METHODS

An extensive Medline search was performed identifying studies in the English language.

RESULTS

The prevalence of diabetes mellitus in infertile men ranges from 0.7% to 1.4%, while the prevalence of infertility in diabetes mellitus men, evaluated in a few studies, ranges from 35% to 51%. Male diabetes mellitus seems to play a negative effect on couple fecundity, while being childless or subfertile men might increase the risk of diabetes mellitus. Available cross-sectional studies investigating semen parameters and male sexual hormones in men with diabetes mellitus are heterogeneous, assessed relatively small cohorts, show often discordant results and frequently are not directly comparable to derive robust conclusions. Two meta-analyses support a negative effect of diabetes mellitus on sperm normal morphology and no effect on sperm total count, with contradictory results regarding other semen parameters. Considering only studies on type 1 diabetes mellitus men, meta-analyses support a negative effect of diabetes mellitus on sperm motility and no effect on sperm total count, with contradictory results regarding other semen parameters. The rate of children observed among type 1 diabetes mellitus men was lower than controls, especially in subjects with a longer diabetes mellitus duration. Couples with a diabetes mellitus male partner undergoing assisted reproduction techniques showed lower pregnancy rates than controls. No study evaluated the impact of diabetes mellitus treatment on semen quality and male fertility.

CONCLUSIONS

Overall, available data show that diabetes mellitus might impair male reproductive health and couple fertility. However, further larger and full of details studies are needed.

Risk factors on testicular function in adolescents

PURPOSE

Adolescence represents an important window for gonadal development. The aim of this review is to carry out a critical excursus of the most recent literature on endogenous and exogenous risk factors related to testicular function, focusing the research on adolescence period.

METHODS

A comprehensive literature search within PubMed was performed to provide a summary of currently available evidence regarding the impact on adolescence of varicocele, cryptorchidism, cancer, diabetes, lifestyle factors, endocrine disruptors, obesity and sexually transmitted diseases. We focused on human studies that evaluated a possible impact of these factors on puberty timing and their effects on andrological health.

RESULTS

Evidence collected seems to suggest that andrological health in adolescence may be impaired by several factors, as varicocele, cryptorchidism, and childhood cancer. Despite an early diagnosis and treatment, many adolescents might still have symptoms and sign of a testicular dysfunction in their adult life and at the current time it is not possible to predict which of them will experience andrological problems. Lifestyle factors might have a role in these discrepancies. Most studies point out towards a correlation between obesity, insulin resistance, alcohol, smoking, use of illegal drugs and testicular function in pubertal boys. Also, endocrine disruptors and sexually transmitted diseases might contribute to impair reproductive health, but more studies in adolescents are needed.

CONCLUSION

According to currently available evidence, there is an emerging global adverse trend of high-risk and unhealthy behaviors in male adolescents. A significant proportion of young men with unsuspected and undiagnosed andrological disorders engage in behaviors that could impair testicular development and function, with an increased risk for later male infertility and/or hypogonadism during the adult life. Therefore, adolescence should be considered a key time for intervention and prevention of later andrological diseases.

The impact of diabetes mellitus type 1 on male fertility: Systematic review and meta-analysis

BACKGROUND

Some evidence suggests that diabetes mellitus type 1 (DM1) could affect male fertility, gonadal axis, semen parameters, and spermatogenesis because of effects of hyperglycemia and insulin deficiency. Anyhow, the exact impact of DM1 on male fertility is unclear.

OBJECTIVES

To review the studies evaluating paternity rate, male gonadal axis, and semen parameters in men with DM1.

MATERIALS AND METHODS

A review of relevant literature from January 1980 to December 2020 was performed. Only studies published in English reporting data on fatherhood (rate of children by natural fertility), hormonal and seminal parameters were included. Out of 14 retrieved articles, the eight studies evaluating semen parameters were meta-analyzed.

RESULTS

The rate of children (four studies) was lower than controls among men affected by DM1, especially in men with a longer duration of disease. The data of gonadal hormonal profile in DM1 men (six studies) are very heterogeneous and a neutral effect of DM1 or a condition of subclinical hypogonadism could not be concluded. Meta-analysis showed that men with DM1 (n = 380), compared with controls (n = 434), have significantly lower normal sperm morphology [-0.36% (-0.66; -0.06), p < 0.05, six studies] and sperm progressive motility [33.62% (-39.13; -28.11), p < 0.001, two studies] and a trend toward a lower seminal volume [-0.51 (-1.03; 0.02), p = 0.06, eight studies], without difference in total sperm count and concentration. Data on scrotal ultrasound and sperm DNA fragmentation are too few. No study evaluated other factors of male infertility, such as transrectal ultrasound, semen infections, sperm auto-antibodies, and retrograde ejaculation.

DISCUSSION

DM1 might impair male fertility and testis functions (endocrine, spermatogenesis), but definition of its actual impact needs further studies.

CONCLUSION

Men with DM1 should be evaluated with a complete hormonal, seminal, and ultrasound workup to better define their fertility potential and need for follow up of testis functions.

Association of diabetes and obesity with sperm parameters and testosterone levels: a meta-analysis

BACKGROUND

The present study performed two distinct meta-analyses with common outcomes (sperm parameters); one was performed in obese individuals (and non-obese controls) and the other in diabetic individuals (and non-diabetic controls).

METHODS

PubMed, Embase, The Cochrane library, Web of Science, Scopus databases were searched to collect clinical studies related to the effects of obesity and diabetes on male sperm from inception to on 1st February 2021. Statistical meta-analyses were performed using the RevMan 5.4 software. Stata16 software was used to detect publication bias. The methodological quality of the included studies was assessed with the Ottawa-Newcastle scale using a star-based system.

RESULTS

A total of 44 studies were finally included in the present study, which enrolled 20,367 obese patients and 1386 patients with diabetes. The meta-analysis results showed that both obesity and diabetes were associated with reduced semen volume (obese versus non-obese controls: mean difference (MD) = - 0.25, 95% CI = (- 0.33, - 0.16), p < 0.001; diabetes versus non-diabetic controls: MD = - 0.45, 95% CI = (- 0.63, - 0.27), p < 0.001), reduced sperm count (obese versus non-obese controls: MD = - 23.84, 95% CI = (- 30.36, - 17.33), p < 0.001; diabetes versus non-diabetic controls: MD = - 13.12, 95% CI = (- 18.43, - 7.82), p < 0.001), reduced sperm concentration (obese versus non-obese controls: MD = - 7.26, 95% CI = (- 10.07, - 4.46), p < 0.001; diabetes versus non-diabetic controls: MD = - 11.73, 95% CI = (- 21.44, - 2.01), p = 0.02), reduced progressive motility (obese versus non-obese controls: MD = - 5.68, 95% CI = (- 8.79, - 2.56), p < 0.001; diabetes versus non-diabetic controls: MD = - 14.37, 95% CI = (- 21.79, - 6.96), p = 0.001), and decreased testosterone levels (obese versus non-obese controls: MD = - 1.11, 95% CI = (- 1.92, - 0.30), p = 0.007; diabetes versus non-diabetic controls: MD = - 0.37, 95% CI = (- 0.63, - 0.12), p = 0.004).

CONCLUSIONS

Current evidence suggests that obesity and diabetes negatively affect sperm parameters in men and are associated with low testosterone levels. Due to the limitation of the number and quality of included studies, the above conclusions need to be verified by more high-quality studies.

Can Antidiabetic Drugs Improve Male Reproductive (Dys)Function Associated with Diabetes?

The alarming increase in the number of diabetic patients worldwide raises concerns regarding the impact of the disease on global health, not to mention on social and economic aspects. Furthermore, the association of this complex metabolic disorder with male reproductive impairment is worrying, mainly due to the increasing chances that young individuals, at the apex of their reproductive window, could be affected by the disease, further contributing to the disturbing decline in male fertility worldwide. The cornerstone of diabetes management is glycemic control, proven to be effective in avoiding, minimizing or preventing the appearance or development of disease-related complications. Nonetheless, the possible impact of these therapeutic interventions on male reproductive function is essentially unexplored. To address this issue, we have made a critical assessment of the literature on the effects of several antidiabetic drugs on male reproductive function. While the crucial role of insulin is clear, as shown by the recovery of reproductive impairments in insulin-deficient individuals after treatment, the same clearly does not apply to other antidiabetic strategies. In fact, there is an abundance of controversial reports, possibly related to the various study designs, experimental models and compounds used, which include biguanides, sulfonylureas, meglitinides, thiazolidinediones/glitazones, bile acid sequestrants, amylin mimetics, as well as sodiumglucose co-transporter 2 (SGLT2) inhibitors, glucagon-like peptide 1 (GLP1), α-glucosidase inhibitors and dipeptidyl peptidase 4 (DPP4) inhibitors. These aspects constitute the focus of the current review.

Antidiabetic therapies and male reproductive function: where do we stand?

Diabetes mellitus has been increasing at alarming rates in recent years, thus jeopardizing human health worldwide. Several antidiabetic drugs have been introduced in the market to manage glycemic levels, and proven effective in avoiding, minimizing or preventing the appearance or development of diabetes mellitus-related complications. However, and despite the established association between such pathology and male reproductive dysfunction, the influence of these therapeutic interventions on such topics have been scarcely explored. Importantly, this pathology may contribute toward the global decline in male fertility, giving the increasing preponderance of diabetes mellitus in young men at their reproductive age. Therefore, it is mandatory that the reproductive health of diabetic individuals is maintained during the antidiabetic treatment. With this in mind, we have gathered the available information and made a critical analysis regarding the effects of several antidiabetic drugs on male reproductive function. Unlike insulin, which has a clear and fundamental role on male reproductive function, the other antidiabetic therapies' effects at this level seem incoherent. In fact, studies are highly controversial possibly due to the different experimental study approaches, which, in our opinion, suggests caution when it comes to prescribing such drugs to young diabetic patients. Overall, much is still to be determined and further studies are needed to clarify the safety of these antidiabetic strategies on male reproductive system. Aspects such as the effects of insulin levels variations, consequent of insulin therapy, as well as what will be the impact of the side effect hypoglycemia, common to several therapeutic strategies discussed, on the male reproductive system are still to be addressed.

High glucose levels affect spermatogenesis: an in vitro approach

Besides known factors that may cause male infertility, systemic diseases such as diabetes mellitus may further exacerbate a decline in male fertility. This metabolic disease, clinically characterised by a hyperglycaemic phenotype, has devastating consequences in terms of human health, with reproductive dysfunction being one of the associated clinical complications. Nonetheless, the mechanisms responsible for such alterations are still poorly understood due to the multiplicity of factors involved in the induced pathophysiological changes. With this in mind, we focused on the main mediator of diabetes-associated alterations and performed an in vitro approach to address the effects of high glucose conditions on spermatogenesis, avoiding other confounding in vivo factors. Mouse (5 days post partum) testis fragments were cultured on agar gel stands at a gas–liquid interface with either 5, 25 or 50 mM D-glucose for 3 weeks. Stereological analysis revealed that high D-glucose levels increased Sertoli cell number (P < 0.05) and decreased tubular luminal area (P < 0.01), suggesting an impairment of this somatic cell type. Moreover, higher proliferative activity in a TM4 Sertoli cell line exposed to high D-glucose was found (P < 0.05) without compromising cell viability (P > 0.05), further suggesting altered Sertoli cell maturation. Overall, high D-glucose concentrations may lead to impairment of Sertoli cell function, which, given their significant role in spermatogenic control, may compromise male fertility.

Diabetes mellitus and functional sperm characteristics: A meta-analysis of observational studies

OBJECTIVE

Insulin resistance and diabetes mellitus (DM) are well defined causes of female infertility. Animal studies present evidence for decreased sperm quality, but conflicting results have been presented in clinically-orientated studies. We sought to evaluate whether DM affects functional sperm characteristics.

STUDY DESIGN

We searched the Medline, Scopus, ClinicalTrials.gov, and Cochrane Central Register of Controlled Trials databases.

RESULTS

DM seems to decrease the seminal volume (MD -0.66ml, 95% CI -1.10, -0.22) and the percentage of motile cells (MD -14.29%, 95% CI -22.76, -5.82) and increase the FSH values (MD 0.47mIU/ml, 95% CI 0.01, 0.93) of men who were screened for infertility. It does not, however, influence the total sperm count (MD 13.16 106 cells, 95% CI -22.75, 49.07), the percentage of normal sperm morphology (-3.06%, 95% CI -6.25, 0.14), or LH (MD 0.65mIU/ml, 95% CI -0.84, 2.13 Supp. Fig. 2) and testosterone values (MD -0.18ng/ml, 95% CI -0.60, 0.24).

CONCLUSION

Current evidence suggests that the presence of DM seems to influence functional sperm characteristics. Firm results are, however, precluded due to the significant heterogeneity of the included studies. Future prospective studies will clarify whether the DM affects semen quality and IVF outcome.

High glucose concentrations per se do not adversely affect human sperm function in vitro

Diabetes mellitus (DM) represents one of the greatest concerns to global health and it is associated with diverse clinical complications, including reproductive dysfunction. Given the multifactorial nature of DM, the mechanisms that underlie reproductive dysfunction remain unclear. Considering that hyperglycemia has been described as a major effector of the disease pathophysiology, we used anin vitroapproach to address the isolated effect of high glucose conditions on human sperm function, thus avoiding otherin vivoconfounding players. We performed a complete and integrated analysis by measuring a variety of important indicators of spermatozoa functionality (such as motility, viability, capacitation status, acrosomal integrity, mitochondrial superoxide production and membrane potential) in human sperm samples after incubation withd- andl-glucose (5, 25, or 50 mM) for 24 and 48 h. No direct effects promoted by 25 or 50 mMd-glucose were found for any of the parameters assessed (P>0.05), except for the acrosome reaction, which was potentiated after 48 h of exposure to 50 mMd-glucose (P<0.05). Interestingly, non-metabolizablel-glucose drastically increased superoxide production (P<0.05) and suppressed sperm motility (P<0.05) and capacitation (P<0.05) after 24 h of treatment, whereas mitochondrial membrane potential (P<0.05), acrosomal integrity (P<0.01) and viability (P<0.05) were later decreased. The overall results suggest that high glucose levelsper sedo not influence human sperm functionin vitro, which stresses the importance of other factors involved in DM pathology. Nevertheless, the absence of metabolizable glucose contributes to a severe impairment of sperm function and thus compromises male fertility.

Free Portuguese abstract: A Portuguese translation of this abstract is freely available athttp://www.reproduction-online.org/content/150/1/77/suppl/DC1.

Impact of gestational diabetes and lactational insulin replacement on structure and secretory function of offspring rat ventral prostate

Clinical and experimental studies have shown that exposure to adverse conditions during the critical stages of embryonic, fetal or neonatal development lead to a significantly increased risk of later disease. Diabetes during pregnancy has been linked to increased risk of obesity and diabetes in offspring. Here, we investigated whether mild gestational diabetes mellitus (GDM) followed or not by maternal insulin replacement affects the ventral prostate (VP) structure and function in male offspring at puberty and adulthood. Pregnant rats were divided into the following 3 groups: control (CT); streptozotocin (STZ)-induced diabetes (D); and D plus insulin replacement during lactation (GDI). The male offspring from different groups were euthanized at postnatal day (PND) 60 and 120. Biometrical parameters, hormonal levels and prostates were evaluated. Mild-GDM promoted reduction in the glandular parenchyma and increased collagen deposition. Insulin replacement during lactation restored the VP morphology. Most importantly, mild-GDM decreased the androgen-induced secretory function as determined by prostatein expression, and insulin replacement reversed this effect. Our results demonstrated that mild GDM impairs VP parenchyma maturation, which is associated with an increase in the fibromuscular stroma compartment. Functionally, the reduction in the VP parenchyma decreases the glandular secretory activity as demonstrated by low expression of prostatein, a potent immunosuppressor factor that protects sperm from immunologic damage into the feminine reproductive tract. This change could lead to impairment of reproductive function in male offspring from diabetic mothers. Maternal insulin replacement during the weaning period apparently restores the prostate function in male offspring.

Production of diabetic offspring using cryopreserved epididymal sperm by in vitro fertilization and intrafallopian insemination techniques in transgenic pigs

Somatic cell nuclear transfer (SCNT) is a useful technique for creating pig strains that model human diseases. However, production of numerous cloned disease model pigs by SCNT for large-scale experiments is impractical due to its complexity and inefficiency. In the present study, we aimed to establish an efficient procedure for proliferating the diabetes model pig carrying the mutant human hepatocyte nuclear factor-1α gene. A founder diabetes transgenic cloned pig was generated by SCNT and treated with insulin to allow for normal growth to maturity, at which point epididymal sperm could be collected for cryopreservation. In vitro fertilization and intrafallopian insemination using the cryopreserved epididymal sperm resulted in diabetes model transgenic offspring. These results suggest that artificial reproductive technology using cryopreserved epididymal sperm could be a practical option for proliferation of genetically modified disease model pigs.

Spermatogenic and sperm quality differences in an experimental model of metabolic syndrome and hypogonadal hypogonadism

The synergistic effect of the co-morbidities that comprise metabolic syndrome (MetS) is increasingly being recognised as an important contributor in the pathology of a broad spectrum of seemingly disparate conditions. However, in terms of male reproductive function, beyond erectile dysfunction, little is known about the influence of this cohort (collectively or separately) on spermatogenesis and sperm quality. The aims of this study were to assess the reproductive tract of a MetS animal model for detrimental changes, to determine whether a group of compounds (advanced glycation end products and their receptor) known to cause cell dysfunction and DNA damage was present and assess whether hypogonadotropic hypogonadism was the main contributing factor for the changes seen. Animals fed a high-fat diet were found to have significantly increased cholesterol, triglycerides, blood glucose, mean arterial pressure and visceral fat levels. Although serum testosterone was decreased, no changes were seen in either testicular or epididymal histology. Immunolocalisation ofNϵ-carboxymethyl-lysine and the receptor for advanced glycation end products was found in the testes, epididymides and sperm of the two treated groups of animals; however, ELISA did not show any difference in protein levels. Similarly, assessment of sperm nuclear DNA (nDNA) fragmentation by acridine orange test did not find significant differences in nDNA integrity. We conclude that the minimal effect on spermatogenesis and sperm quality seen in our model is probably due to the moderate increase of blood glucose rather than the hypogonadism.

[The influence of diabetes mellitus on male reproductive function: a poorly investigated aspect of male infertility]

Whilst diabetes mellitus is known to have many systemic complications, male infertility, beyond impotence, retrograde ejaculation and hypogonadism, has not been widely recognised to be one of them. Due to the paucity of studies and inconsistencies regarding the condition's impact on semen quality, few fertility specialists consider the condition noteworthy. As a consequence little information exists as to its prevalence amongst infertile men. Recently the prevailing view has been challenged by findings showing that diabetes induces subtle molecular changes that are important for sperm quality and function. Diabetic men have been found to have a significantly higher percentage of sperm with nuclear DNA damage, a factor known to be associated with compromised fertility and increased miscarriage rates. The mechanism by which this diabetes-related sperm nDNA damage occurs remains unknown. The identification of high levels of advanced glycation end products (AGEs) and their receptor (RAGE) throughout the male reproductive tract coupled to changes in testicular metabolite levels and spermatogenic gene expression suggest that glycation may play an integral role in oxidative stress which in turn causes sperm nDNA damage. As glycation is a normal consequence of life and has been implicated in DNA fragmentation in a variety of seemingly unconnected conditions, it may constitute a common mechanism for the damage seen in sperm DNA.

Prise en charge de l’infécondité dans les troubles de l’éjaculation: avis conjoints de l’andrologue, du biologiste et du gynécologue

Quatre-vingts pour cent des hommes qui présentent des troubles de l’éjaculation sont en âge de procréer, mais seul 5 à 10 % en sont spontanément capables. Du sperme antérograde et/ou rétrograde peut être recueilli par éjaculation assistée en association à des traitements pharmacologiques (chlorhydrate de minodrine-vibroéjaculation). En cas d’échecs de recueil de sperme et d’azoospermie, l’extraction chirurgicale des spermatozoïdes épididymaires ou testiculaires permet d’obtenir des spermatozoïdes, en quantité généralement moins importante que les techniques d’éjaculation assistée, mais non infectés et dépourvus de plasma séminal (souvent délétère dans les troubles de l’éjaculation). Même en cas d’éjaculation antérograde, il est impératif de recueillir les urines systématiquement à la recherche d’une éjaculation rétrograde, fréquente dans les troubles de l’éjaculation. Au laboratoire, l’analyse du sperme et de l’urine s’effectue par les méthodes de routine standardisées. La plupart des hommes présentant des troubles de l’éjaculation ont un sperme de mauvaise qualité (asthénospermie, nécrospermie, leucospermie). Les étiologies de la dégradation des paramètres du sperme sont multifactorielles, d’origine centrale et périphérique (testiculaire et extratesticulaire). Optimiser la qualité du sperme et des spermatozoïdes reste un challenge d’actualité dans les troubles de l’éjaculation. Si la cryopréservation doit être systématique, l’utilisation du sperme frais optimisé a généralement la préférence. Réussir à obtenir du sperme offre au couple une chance de grossesse naturelle (rarement) grâce à une éjaculation coïtale, par auto-insémination, par insémination intra-utérine, par fécondation in vitro conventionnelle (FIVc) ou injection intracytoplasmique de spermatozoïdes (ICSI) dans l’ovocyte. Dans les troubles de l’éjaculation, la prise en charge de la fécondité de l’homme doit être la plus rapide possible. Elle s’effectue conjointement à celle de la femme par une équipe coordonnant l’andrologue, le biologiste et le gynécologue.

Distribution of the receptor for advanced glycation end products in the human male reproductive tract: prevalence in men with diabetes mellitus

BACKGROUND

Diabetics have a significantly higher percentage of sperm with nuclear DNA (nDNA) fragmentation and increased levels of advanced glycation end products (AGEs), in their testis, epididymis and sperm. As the receptor for AGEs (RAGE) is important to oxidative stress and cell dysfunction, we hypothesise, that it may be involved in sperm nDNA damage.

METHODS

Immunohistochemistry was performed to determine the presence of RAGE in the human testis and epididymis. A comparison of the receptor's incidence and localization on sperm from 10 diabetic and 11 non-diabetic men was conducted by blind semi-quantitative assessment of the immunostaining. Enzyme-linked immunosorbent assay analysis ascertained RAGE levels in seminal plasma and sperm from 21 diabetic and 31 non-diabetic subjects. Dual labelling immunolocalization was employed to evaluate RAGE's precise location on the sperm head.

RESULTS

RAGE was found throughout the testis, caput epididymis, particularly the principle cells apical region, and on sperm acrosomes. The number of sperm displaying RAGE and the overall protein amount found in sperm and seminal plasma were significantly higher in samples from diabetic men (P < 0.01, P < 0.0001 and P < 0.0001, respectively).

CONCLUSIONS

The presence of RAGE implies that it may play a central role in sperm nDNA damage particularly in diabetic men where the levels are elevated.

Experimental diabetes has adverse effects on the differentiation of ventral prostate during sexual maturation of rats

Diabetes mellitus of both type I (insulin-dependent) and type II (noninsulin-dependent) has adverse effects on male sexual and reproductive functions in adolescent boys and men, which include impairment of spermatogenesis, reduced sperm count, serum testosterone and seminal fluid volume, impotency, and loss of libido. Streptozotocin (STZ)-induced diabetes in rats provides a relevant model to study reproductive dysfunction under diabetic conditions, as they exhibit a number of deficits in reproductive function that resemble those seen in human diabetics. Therefore, the present investigation is aimed to understand the effects of STZ diabetes on the structure and development of ventral prostate during the critical period of sexual maturation in rats. Prepubertal (40-days-old) male Wistar rats were made diabetic by single injection of STZ (120 mg/kg body weight, intraperitoneally). Induction of diabetes was confirmed by serum insulin titer, hyperglycemia, and polyuria. To another set of STZ-diabetic rats, after 3 days of diabetes induction, insulin was replaced at a dose of 3 U/100 g body weight, subcutaneously in two equally divided doses at 8:00 AM and 6:00 PM. Diabetes caused regression of prostate, leading to a decrease in the absolute weight. Histologically, glandular epithelium has undergone shrinkage with transformation of acinar cells into low cuboidal type with less prominent secretory granules and blebs. Nevertheless, the secretory activity was not totally abolished. Interstitial space was increased due to shrinkage of glandular epithelium. Histomorphometric studies on the tubular diameter, volume and surface density of acinar epithelium, lumen, and stroma also support regressive changes in prostate. Insulin replacement prevented the detrimental effects of diabetes partially. These findings implicate the adverse effects of STZ diabetes on the differentiation of ventral prostate during sexual maturation.

Enhanced mitochondrial testicular antioxidant capacity in Goto-Kakizaki diabetic rats: role of coenzyme Q

Because diabetes mellitus is associated with impairment of testicular function, ultimately leading to reduced fertility, this study was conducted to evaluate the existence of a cause-effect relationship between increased oxidative stress in diabetes and reduced mitochondrial antioxidant capacity. The susceptibility to oxidative stress and antioxidant capacity (in terms of glutathione, coenzyme Q, and vitamin E content) of testis mitochondrial preparations isolated from Goto-Kakizaki (GK) non-insulin-dependent diabetic rats and from Wistar control rats, 1 yr of age, was evaluated. It was found that GK mitochondrial preparations showed a lower susceptibility to lipid peroxidation induced by ADP/Fe(2+), as evaluated by oxygen consumption and reactive oxygen species generation. The decreased susceptibility to oxidative stress in diabetic rats was associated with an increase in mitochondrial glutathione and coenzyme Q9 contents, whereas vitamin E was not changed. These results demonstrate a higher antioxidant capacity in diabetic GK rats. We suggest this is an adaptive response of testis mitochondria to the increased oxidative damage in diabetes mellitus.

Reproductive effects of nontesticular illness

Diseases in other organs may impair the male reproductive system. Acute critical conditions such as severe trauma, surgery, myocardial infarction, burns, liver failure, intoxication, or starvation are associated with suppression of gonadotropin secretion and secondary hypogonadism. With chronic illnesses, a primary testicular disorder with elevated gonadotropin levels may occur. This may be associated with increased peripheral conversion of androgens to estrogens, resulting in clinical presentation of combined androgen deficiency and estrogen excess. The association of hypogonadism and feminization with cirrhosis of the liver is a classic example. Types of hypogonadism that may occur with chronic anemia, chronic renal failure, chronic spinal cord injury, thyroid diseases, Cushing's syndrome, diabetes mellitus, obesity, HIV infection, neoplasia, and other chronic illnesses are also described. Numerous drugs have side effects on the reproductive system.

Serum and urinary levels of pituitary--gonadal hormones in insulin-dependent and non-insulin-dependent diabetic males with and without neuropathy

Diabetic neuropathies were studied in 100 insulin-dependent diabetes mellitus patients, 314 non-insulin-dependent diabetes mellitus patients with and without an objective evidence of neuropathy (age span, 15-80 years; duration of diabetes distributed over 1-33 years), and their age-matched nondiabetic controls. Serum and urinary levels of pituitary-gonadal hormones were evaluated in the diabetic subjects. There were striking results, i.e., a significantly low serum total and serum free (urinary) testosterone level (p < .0005) and a significantly high serum and urinary FSH and LH and serum prolactin level (p < .0005), specifically in the neuropathic diabetic patients, suggesting a series of pathological reactions in the smooth musculature of genital organs characterized by an increase in the interstitial thickness of seminiferous tubules, peritubular and intertubular fibrosis, and tubular sclerosis. Testicular necrosis, probably due to neuropathy, provided an additional aid to confirm these findings. A decrease in semen volume and sperm motility in the diabetic neuropathic patients further suggested the involvement of the entire smooth musculature of the reproductive tract, leading to atonia of the bladder and urethra. Such complications are purely neurogenic. The low serum and urinary testosterone levels and increased serum and urinary FSH and LH and serum prolactin levels in the diabetic men with neuropathy suggest gonadal disorder (hypogonadotropic hypogonadism), which may be due to testicular necrosis and thickening of seminiferous tubules, causing autonomic lesion.

Semen characteristics and diabetes mellitus: significance of insulin in male infertility

A study was made of semen quality and serum hormonal profiles (FSH, LH, prolactin, testosterone) of patients with type I diabetes mellitus. Semen parameters and levels of prolactin and testosterone were significantly altered in the diabetic state. The concentration of insulin in serum and seminal plasma and the serum levels of FSH, LH, and testosterone were measured in 80 men classified in the following groups: fertile subjects, infertile normoglycemic subjects, subjects with carbohydrate intolerance, and excretory and secretory azoospermic subjects. In all groups, seminal insulin concentrations were higher than those obtained in serum. The hormone appears to freely cross the blood-testis barrier, there to be concentrated in the semen. The levels of insulin in serum and seminal plasma did not correlate with semen parameters and are not suitable markers of seminal quality. For unknown reasons, the concentrations of insulin in seminal plasma were lower in the subjects suffering from carbohydrate intolerance.

Testicular alterations in the nonobese diabetic mouse

The nonobese diabetic (NOD) mouse was used as a model for evaluating alterations in testicutar structure. The NOD mouse exhibits diabetic manifestations on an apparently autoimmune basis and thus resembles human type 1 insulin-dependent diabetes mellitus. Testicular samples were obtained from animals with and without diabetic manifestations at various ages. The principal changes noted on histological examination were in the seminiferous tubules, including germ cell degeneration, disruption of spermatogenesis, tubular fibrosis, and intratubular calcification. These effects were diffuse and extensive in animals with severe hyperglycemia. In those with normal and borderline elevated glucose levels, focal tubular damage was found to occur in a patchy distribution. The changes included disorganization of maturation, malorientation of spermatids, and hypospermatogenesis. Electron microscopic studies also indicated effects on Sertoli cells and the peritubular tissue. There was no evidence of mononuclear cell infiltration or vascular abnormalities in any of the testicular specimens. The findings indicate that the NOD mouse may be a useful model for understanding the development of pathological changes in the testis in insulin-dependent diabetes.

Diabetes mellitus/male infertility

Diabetes mellitus (DM), associated with very subtle disorders, affects, either directly or indirectly, various functions of the reproductive system. Adequate, regular, and timely therapy may prevent or delay these disorders. The T synthesis disorder is caused by molecular changes at the level of Leydig cells and may lead to other disorders in all target organs and tissues. The close correlation between Leydig and Sertoli cells function, i.e., between spermatogenesis and second sex glands function, results in certain anomalies in diabetic patients' spermiograms. Parallel lesions associated with DM, through CNS (hypothalamus-hypophysis), and endocrine profile are indirectly intensified or induced by these disorders, which reflect dysfunction of homeostatic balance in carbohydrate metabolism. Sexual dysfunction in all its forms (reduced erection, impotence, and other libido dissociations) is an accompanying phenomenon of the diabetic disease. However, manifestations of these disorders are related to the regulation of carbohydrate metabolism and to the duration of disease. The duration of disease is not necessarily correlated with sexual dysfunction. Even carbohydrate metabolism remains within normal range in addition to other lesions, diabetes leads gradually but progressively to premature aging of body cells.