Wiley
0196-3635
1939-4640
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The Action of Calcitonin on the TM<sub>4</sub> Sertoli Cell Line and on Rat Sertoli Cell‐Enriched Cultures The effects of synthetic salmon calcitonin on primary Sertoli cell‐enriched cultures and on an established cell line (TM4 cells, derived from immature mouse Sertoli cells) were studied. Synthetic salmon calcitonin stimulated the conversion of [3 H]adenine to [3 H]cyclic AMP in both cell systems. In addition, this peptide stimulated the secretion of rABP in primary Sertoli cellenriched cultures prepared from rat testis. Calcitonin also increased the total concentration of both androgen and estrogen receptors in TM4 cells. Because cAMP analogs decreased androgen and estrogen receptor concentrations, the effect of calcitonin on sex steroid receptors may not be mediated by its effect on cyclic AMP in these cells. The possibility that the action of synthetic salmon calcitonin on the receptors might be mediated by a change in cellular Ca2+ was investigated. Lowering extracellular Ca2+ concentrations from 1.5 mM to less than 0.01 mM markedly reduced the concentration of androgen and estrogen receptors; restoration of Ca2+ to 1.5 mM returned receptor levels to normal. When the receptor concentrations were decreased by lowering extracellular Ca2+ concentrations to 0.5 mM, treatment with the calcium ionophore, A23187, restored receptor levels to normal. Although the calcium channel blocker, verapamil, decreased receptor levels, calcitonin partially counteracted its effect. Trifluoperazine, an inhibitor of calmodulin, also diminished androgen and estrogen receptor levels in the cytosol of TM4 cells. It was concluded that calcitonin stimulates the formation of cyclic AMP and the secretion of rABP by Sertoli cells. This peptide also increases the concentration of androgen and estrogen receptors, possibly by a mechanism that is, in part, Ca2+ ‐mediated. These results, along with those on Leydig cells, suggest that calcitonin could be a regulator of testicular function.
Tập 10 Số 4 - Trang 321-331 - 1989
Human Glyceraldehyde 3‐Phosphate Dehydrogenase‐2 Gene Is Expressed Specifically in Spermatogenic Cells ABSTRACT: Although the process of glycolysis is highly conserved in eukaryotes, several glycolytic enzymes have unique structural or functional features in spermatogenic cells. We previously identified and characterized the mouse complementary DNA (cDNA) and a gene for 1 of these enzymes, glyceraldehyde 3‐phosphate dehydrogenase‐s (Gapds) . This gene is expressed only in spermatids. The enzyme appears to have an essential role in energy production required for fertilization, and it is reported to be susceptible to inhibition by certain environmental chemicals. We have now cloned and sequenced the cDNA for the human homo‐logue of glyceraldehyde 3‐phosphate dehydrogenase (GAPD2) and determined the structure of the gene. The messenger RNA (mRNA) was detected in testis, but not in 15 other human tissues analyzed by Northern blot technique. The deduced GAPD2 protein contains 408 amino acids and is 68% identical with somatic cell GAPD. GAPD2 has a 72‐amino acid segment at the amino terminal end that is not present in somatic cell GAPD. This segment is prolinerich but contains smaller stretches of polyproline and is 30 amino acids shorter than the comparable segment of mouse GAPDS. The structure of the human GAPD2 gene was determined by polymerase chain reaction (PCR) to identify exonintron junctions in a genomic clone and in total genomic DNA. The locations of these junctions in the GAPD2 gene corresponded precisely to those of the 11 exonintron junctions in the mouse Gapds gene. Immunohistochemical studies found that GAPD2 is located in the principal piece of the flagellum of human spermatozoa, as are GAPDS in mouse and rat spermatozoa. GAPD2 extracted from human spermatozoa and analyzed by Western blot technique migrated with an apparent molecular weight of ∼56 000, although the calculated molecular weight is 44501. The conserved nature of the mouse, rat, and human enzymes suggests that they serve similar roles in these and other mammalian species.
Tập 21 Số 2 - Trang 328-338 - 2000
Significance of Reactive Oxygen Species and Antioxidants in Defining the Efficacy of Sperm Preparation Techniques The mechanisms responsible for mediating the influence of sperm preparation protocols on human sperm function have been investigated. Techniques that involved the separation of motile spermatozoa prior to centrifugation were found to yield sperm suspensions of highest quality. If the spermatozoa were centrifuged prior to isolation of the motile cells, sperm function was impaired. The detrimental effects of centrifugation were associated with a sudden burst of reactive oxygen species production by a discrete subpopulation of cells (characterized by significantly diminished motility and fertilizing capacity) that could be separated from normal functional spermatozoa on Percoll gradients. If unfractionated sperm suspensions were subjected to centrifugation, the reactive oxygen species generated by this subpopulation impaired the functional competence of normal spermatozoa in the same suspension. Assessment of the ability of the antioxidants, butylated hydroxytoluene, and vitamin E, to curtail the peroxidative damage inflicted by such cells in response to centrifugation revealed a significant improvement of sperm function in the presence of vitamin E.
Tập 9 Số 6 - Trang 367-376 - 1988
Varicocele and Fertility: Relationship Between Testicular Volume and Seminal Parameters Before and After Treatment ABSTRACT: Varicocele is a condition of varicosity and tortuosity of the pampiniform plexus that is often associated with a reduction in the volume of the affected testicle. Today there is much debate about how much the varicocele actually damages the reproductive system and the mechanism through which this occurs. Furthermore, it has not yet clearly been established if treatment is truly useful to restore testicular function. The goal of this study was to evaluate changes in the volume of the affected testis after treatment and to examine any correlations between volume and seminal parameters. We evaluated 43 patients with left idiopathic varicocele with ultrasound scan of the testis before and after surgery; testicular volume was obtained using the ellipsoid formula. We also examined semen parameters before and at an average time of 1 year after the procedure, using the WHO indications. We performed 2 statistical analyses, comparing changes in testicular volume before and after surgery, and volume with seminal parameters. Statistical analysis shows a significant increase of testicular volume after varicocele treatment (P < .05). Furthermore, the total number of spermatozoa and fast progressive spermatozoa rates significantly increased after surgery (respectively P < .05 and P < .01) (Figure 1). The Spearman correlation coefficient shows a good relationship between testicular volume and total number of spermatozoa (r = .445; P = .01). Our data point to the possibility that the affected testicle could benefit in terms of trophism and function after varicocele treatment. Ultrasound scan at follow‐up permits assessment of not only the presence of recurrence, but it is also useful for evaluating trophism.
Tập 27 Số 4 - Trang 548-551 - 2006
Hypoxia‐Inducible Factor‐1α Is Constitutively Expressed in Murine Leydig Cells and Regulates 3β‐Hydroxysteroid Dehydrogenase Type 1 Promoter Activity ABSTRACT: Hypoxia‐inducible factor‐1α (HIF‐1α) is a transcription factor that plays an essential role in oxygen homeostasis. HIF‐1α is constitutively made in cells; however, it is ubiquitinated and degraded under normoxic conditions. Hypoxia prevents the ubiquitination of HIF‐1α, resulting in stabilization of the protein and activation of target genes. Because of its vascular arrangement and the high metabolic demand of spermatogenesis, the testis has been described previously as functioning on the brink of hypoxia; thus, we have hypothesized that HIF‐1α is constitutively expressed and stabilized in the testis, where it could play a role in testicular homeostasis. Western blot analysis using nuclear proteins from liver, kidney, and testis revealed the presence of HIF‐1α only in the testis. Immunohistochemistry confirmed this result and revealed that HIF‐1α was specifically located in interstitial Leydig cells. Electromobility shift assays employing nuclear extracts from the TM3 Leydig cell line revealed that these cells express HIF‐1α that is capable of binding DNA under normoxic conditions. Furthermore, we found that protein levels can be increased further when the TM3 cells are cultured under hypoxic conditions. Finally, transient transfections of TM3 Leydig cells revealed that the promoter of the mouse 3β‐hydroxysteroid dehydrogenase type 1 (Hsd3b1) gene, which encodes a key enzyme in testosterone production, is a potential target of HIF‐1α. In conclusion, HIF‐1α is constitutively present in the Leydig cells of the murine testis, where it potentially regulates Hsd3b1 transcription, and thus male reproductive function.
Tập 30 Số 2 - Trang 146-156 - 2009
The Actions of Calcitonin on the TM<sub>3</sub> Leydig Cell Line and on Rat Leydig Cell‐Enriched Cultures Studies demonstrating calcitonin receptors on Leydig cells have suggested that these cells may be one of the many sites affected by this peptide. To investigate this possibility, the effect of synthetic salmon calcitonin on the TM3 Leydig cell line (derived from immature mouse Leydig cells) and on primary Leydig cell‐enriched preparations was examined. Synthetic salmon calcitonin stimulated the conversion of [3 H]adenine to [3 H]cyclic AMP in TM3 cells. In addition, the hormone stimulated the basal secretion of testosterone in both TM3 cell‐ and Leydig cell‐enriched cultures and potentiated the action of hCG on Leydig cell‐enriched cultures. Synthetic salmon calcitonin also increased the concentration of androgen and estrogen receptors in cultured TM3 Leydig cells by 2‐ and 4‐fold, respectively, when added to the culture medium (1 μg/ml). The fact that 8‐bromo‐cyclic AMP decreased both androgen and estrogen receptor concentrations suggested that the effect of calcitonin on sex steroid receptors is not mediated by its effect on cyclic AMP in these cells. The possibility that the action of calcitonin on steroid receptors might be mediated by another messenger such as calcium (Ca2+ ) was therefore considered. Progressively lowering the concentration of Ca2+ in the culture medium of the cells from 1.5 mM to less than 0.01 mM decreased the concentration of both androgen and estrogen receptors. Returning the Ca2+ concentration to normal levels (1.5 mM) restored steroid receptor levels. Receptor levels were also decreased when the extracellular Ca2+ concentration was lowered to 0.5 mM, and treatment with the Ca2+ ionophore, A23187 (1 μM), restored receptor levels to normal. The calcium channel blocker, verapamil, decreased the androgen receptor concentration but unexpectedly increased the concentration of estrogen receptors. It was concluded that calcitonin stimulates cAMP formation and testosterone secretion, and increases the concentration of sex steroid receptors. These observations provide evidence that the previously demonstrated calcitonin receptors on Leydig cells may be coupled to several biologic responses in this cell type.
Tập 10 Số 4 - Trang 311-320 - 1989
Perceived Ejaculate Volume Reduction in Patients With Erectile Dysfunction: Psychobiologic Correlates ABSTRACT: The disorders of orgasm/ejaculation encompass a heterogeneous group of dysfunctions including premature ejaculation, delayed ejaculation, and perceived ejaculate volume reduction (PEVR). The aim of this study was to explore specific associations of PEVR in a consecutive series of 3141 patients (mean age, 51.6 ± 13.1 years) seeking consultation for erectile dysfunction (ED). Among these, 71 were excluded because they underwent prostate surgery. Different clinical and biochemical factors were evaluated along with parameters derived from the Structured Interview on Erectile Dysfunction evaluating the contribution of organic, relational, and intrapsychic factors to ED. After adjustment for confounders, PEVR was specifically associated with the use of androgen deprivation therapy as well as with different other medications including α‐blockers, serotonergic reuptake inhibitor antidepressants, and angiotensin‐converting enzyme inhibitors/angiotensin receptor blockers. A higher prevalence of diabetes mellitus and hypogonadism was observed in patients with PEVR compared with the rest of the sample (23.0% vs 14.1% and 9.1% vs 5.3% respectively; both P < .05). In addition, different sexual parameters such as severe ED (hazard ratio [HR] = 1.25 [1.11–1.41]; P < .0001) and patient's (HR = 1.53 [1.38–1.70]; P < .0001) and partner's (HR = 1.21 [1.07–1.36]; P < .005) hypoactive sexual desire (HSD) were also significantly related to PEVR. Furthermore, PEVR was associated with an impairment of both the relational and intrapsychic components of ED. In a multivariate model, adjusting for age, body mass index, smoking habits, and medications, hypogonadism, diabetes mellitus, severe ED, and patient's and partner's HSD were all independently associated with PEVR. Our results indicate that PEVR is important not only for couple reproductive purposes but also appears to have a distinct role in the couple's sexual performance.
Tập 32 Số 3 - Trang 333-339 - 2011
Assessment of the Relational Factor in Male Patients Consulting for Sexual Dysfunction: The Concept of Couple Sexual Dysfunction ABSTRACT: In a consecutive series of 1140 male subjects reporting a stable couple relationship and different degrees of sexual dysfunction, we evaluated the impact of relational factors, as assessed by the Structured Interview on Erectile Dysfunction (SIEDY) Scale 2 (exploring, as reported by the patient, menopausal symptoms, partner's medical illness interfering with sexual activity, and reduced partner desire and climax). We found that the SIEDY Scale 2 is significantly and independently associated with erectile dysfunction (ED), delayed ejaculation, hypoactive sexual desire, and decreased frequency of intercourse. SIEDY Scale 2 scores are associated with an advanced age of the partner and a long couple relationship, independently from patient's age. In addition, an increased relational factor correlates with increased extramarital affairs, conflicts in the couple, alcohol abuse, and presence of depressive symptoms, as assessed by the Middlesex Hospital Questionnaire. Our results should encourage the andrologist to consider the context in which sexual symptoms develop, analyzing the relationship and partner's behaviors and diseases. Resolving, or at least ameliorating, the relational background and the sexual framework might help in treating male sexual dysfunction.
Tập 27 Số 6 - Trang 795-801 - 2006
Psycho‐Biological Correlates of Free‐Floating Anxiety Symptoms in Male Patients With Sexual Dysfunctions ABSTRACT: Anxiety has a relevant impact on everyday life, including sexual life, and therefore is considered the final common pathway by which social, psychological, and biological stressors negatively affect sexual functioning. The aim of this study is to define the psycho‐biological correlates of free‐floating anxiety in a large sample of patients complaining of erectile dysfunction (ED)‐based sexual problems. We studied a consecutive series of 882 ED patients using SIEDY©, a 13‐item structured interview, composed of 3 scales that identify and quantify organic, relational, and intrapsychic domains. MHQ‐A scoring from Middlesex Hospital Questionnaire (MHQ) was used as a putative marker of free‐floating anxiety symptoms (AS). Metabolic and hormonal parameters, nocturnal penile tumescence (NPT) test, and penile Doppler ultrasound (PDU) examination were also performed. MHQ‐A score was significantly higher in patients complaining of difficulties in maintaining erection and in those reporting premature ejaculation (6.5 ± 3.3 vs 5.8 ± 3.3 and 6.6 ± 3.3 vs 6.1 ± 3.3, respectively; both P < .05). Moreover, ASs were significantly correlated to life stressors quantified by SIEDY© scale 2 (relational component) and scale 3 (intrapsychic component) scores, as dissatisfaction at work or within the family or couple relationships. Among physical, biochemical, or instrumental parameters tested, only end‐diastolic velocity at PDU was significantly (P < .05) related to ASs. In conclusion, in patients with ED‐based sexual problems, ASs are correlated to many relational and life stressors. Conversely, organic problems are not necessarily associated with MHQ‐A score.
Tập 27 Số 1 - Trang 86-93 - 2006
Relationship of Spermatozoal Migration in Cervical Mucus to Bovine Fertility Frozen bovine semen from males of wellestablished, generally high fertility levels was thawed and used in three experiments for In vitro capillary tube migration through cervical mucus. Bovine cervical mucus from individual heifers or a group of heifers was evaluated in these assays. Correlations between spermatozoal migration and bull fertility were small and not significant. Significant differences in spermatozoal migration distances were due to bulls, source of mucus, and storage time of mucus before use in the assay. These differences did not appear to affect the correlations obtained, but they require that the sperm migration test be standardized relative to sources of mucus and storage time if different seminal specimens are to be compared.
Tập 2 Số 2 - Trang 103-107 - 1981