Investigation of the neural target level of hyperthyroidism in premature ejaculation in a rat model of pharmacologically induced ejaculation

Thyroid diseases and female sexual dysfunctions

INTRODUCTION

Female sexual dysfunctions (FSDs) have received little attention in the context of thyroid diseases, despite the high prevalence of both conditions.

OBJECTIVES

This review aims to update and summarize the state of knowledge on the association between thyroid diseases and FSDs and to investigate the complex mechanisms through which thyroid hormone imbalance can impact female sexual health in the context of the biopsychosocial model.

METHODS

A comprehensive literature search was performed through the PubMed, MEDLINE, and Scopus databases, using the following keywords: "female sexual function," "sexual dysfunction," "hypoactive sexual desire disorder," "thyroid disease," "thyroiditis," "hypothyroidism," and "hyperthyroidism."

RESULTS

To date, well-designed studies that describe the relationship between FSDs and thyroid disorders are lacking. However, despite the limitations on available studies, current data indicate that sexual alterations are frequently associated with thyroid diseases in women. A complex interplay of direct and indirect hormonal and nonhormonal mechanisms has been hypothesized, including hormonal changes, neurotransmitter imbalance, reduced nitric oxide release, mood disorders, and other systemic consequences of both hypothyroidism and hyperthyroidism. Thyroid hormone receptors have also been identified in the genitourinary system.

CONCLUSIONS

In a clinical setting, physicians should investigate the sexuality of patients consulting for thyroid disease. At the same time, an evaluation of thyroid function should be performed in patients presenting with FSD, especially after menopause, when the risk of thyroid diseases and FSDs increases strongly.

Systematic review and meta-analysis for the value of thyroid disorder screening in men with ejaculatory dysfunction

OBJECTIVE

To demonstrate evidence from available clinical studies to clarify the scientific points that have been achieved in relation to thyroid disorders and ejaculatory dysfunction (EjD).

DATA SOURCES

Clinical trial articles published in English on Medline.

ELIGIBILITY CRITERIA

Clinical studies that investigated the association of thyroid disorders with the ejaculatory function of subjects and the trials evaluating the effect of thyroid dysfunction treatment on the ejaculatory function of the subjects were eligible.

SYNTHESIS METHODS

We searched Medline with "ejaculation" and different combinations of "thyroid," "serum TSH," "serum T3," "serum T4" keywords in PubMed.

RESULTS

Standardised mean serum thyroid-stimulating hormone (TSH) levels in premature ejaculation (PE) sufferers differed from non-PE control subjects (P = .05). Hyperthyroidism was associated with increased odds among PE subjects (OR = 2.0, P = .03). Delayed ejaculation was seen with increased odds in hypothyroid patients compared with hyperthyroidism patients (OR = 57, P = .0001). Serum TSH and mean intra-vaginal ejaculation latency time (IELT) of the subjects showed a correlation both before and after treatment for thyroid disorder. Treatment of thyroid disorders improved the mean IELT measures of the subjects. The overall estimate of the effect of hyperthyroidism treatment on mean IELT was .64 (P = .0001) in the random-effects model.

LIMITATIONS

The low quality and quantity of evidence from available studies limited the interpretation of our study findings.

CONCLUSIONS

The causal relationship between EjD and thyroid disorders remains to be clarified. Sufferers of delayed ejaculation acquired PE subjects, and PE sufferers who have accompanying erectile dysfunction and/or anxiety may benefit from thyroid disorder investigation.

Redefining a sexual medicine paradigm: subclinical premature ejaculation as a new taxonomic entity

Premature ejaculation (PE) and poor ejaculatory control are multidimensional sexual symptoms estimated to affect almost one-third of men, severely impairing the overall quality of life of patients and their partners. However, patients who do not completely fulfil the definition criteria for PE rarely receive a diagnosis or adequate treatment, with the risk of subsequent progression from initial, subclinical symptoms to clinically overt PE, frequently with other sexual comorbidities. Thus, the current definitions of PE warrant review, in order to consider and propose a new taxonomy encompassing other unaddressed, crucial clinical aspects of PE. These newly proposed criteria include the recommendation for a primary screening for erectile dysfunction (ED), as PE and ED can be comorbid in up to 50% of patients but have never before been considered as a unified clinical entity. In order to facilitate clinical practice and improve clinical management of men with PE and comorbid conditions, we propose and define the new taxonomic clinical entities of subclinical PE (SPE) and loss of control of erection and ejaculation (LCEE). Application of these diagnoses to men who meet the criteria for SPE and/or LCEE, but not the overt conditions, could improve access to treatment for these patients and reduce progression to the more serious clinical disorder.

Effects of the dopamine D3 receptor agonist 7-hydroxy-2-(di-N-propylamino) tetralin in hyperthyroidism-induced premature ejaculation rat model

Various factors are involved in the aetiology of premature ejaculation (PE). Hyperthyroidism is one of the causes of acquired PE, but the exact mechanism by which it causes the disorder is not yet understood. The aim of this study was to evaluate the role of the dopaminergic system in hyperthyroidism-induced PE by the intracerebroventricular microinjection of the preferentially active dopamine receptor agonist 7-hydroxy-2-(di-N-propylamino) tetralin (7-OH-DPAT) in a rat model of this disorder. Wistar rats were randomly divided into hyperthyroid and control groups, and ejaculation was induced by the ICV administration of 7-OH-DPAT. To evaluate the emission and expulsion phases of ejaculation, measurements of seminal vesicle pressure (SVP) and electromyographic recordings of the bulbospongiosus muscle were taken. The interval between the 7-OH-DPAT administration and the first ejaculation was significantly less in the hyperthyroid group (p < .01) than in the control group, and the maximum amplitude of the SVP values revealed a statistically significant difference between the groups (p < .01). The intervals between contractions of the seminal vesicle and bulbospongiosus muscles were also significantly less in the hyperthyroid group (p = .0187) than in the control group. No other results differed significantly between the groups. This study determined that hyperthyroidism altered only the emission phase of ejaculation.

Assessment of hormonal activity in patients with premature ejaculation

Purpose

Premature ejaculation is considered the most common type of male sexual dysfunction. Hormonal controls of ejaculation have not been exactly elucidated. The aim of our study is to investigate the role of hormonal factors in patients with premature ejaculation.

Materials and Methods

Sixty-three participants who consulted our outpatient clinics with complaints of premature ejaculation and 39 healthy men as a control group selected from volunteers were included in the study. A total of 102 sexual active men aged between 21 and 76 years were included. Premature ejaculation diagnostic tool questionnaires were used to assessment of premature ejaculation. Serum levels of follicle stimulating hormone, luteinizing hormone, prolactin, total and free testosterone, thyroid-stimulating hormone, free triiodothyronine and thyroxine were measured.

Results

Thyroid-stimulating hormone, luteinizing hormone, and prolactin levels were significantly lower in men with premature ejaculation according to premature ejaculation diagnostic tool (p=0.017, 0.007 and 0.007, respectively). Luteinizing hormone level (OR, 1.293; p=0.014) was found to be an independent risk factor for premature ejaculation.

Conclusions

Luteinizing hormone, prolactin, and thyroid-stimulating hormone levels are associated with premature ejaculation which was diagnosed by premature ejaculation diagnostic tool questionnaires. The relationship between these findings have to be determined by more extensive studies.

Dapoxetine and the treatment of premature ejaculation

Background

Premature ejaculation (PE) is the most common male sexual complaint. Off-label oral selective serotonin reuptake inhibitors (SSRIs) are commonly prescribed for the treatment of PE. Dapoxetine is a short-acting SSRI specifically designed for on-demand use. The objective of this communication is to summarize the clinical and physiological evidence regarding the role of the serotonergic pathway and specifically dapoxetine in the treatment of PE.

Methods

A PubMed search was conducted on articles reporting data on dapoxetine for the treatment of PE. Articles describing the pathophysiology and treatment options for PE were additionally included for review.

Results

The etiology of PE is multi-factorial in nature. There are many treatment options for PE such as psychological/behavioral therapy, topical anesthetic agents, phosphodiesterase type 5 (PDE-5) inhibitors, and tramadol hydrochloride. SSRIs play a major role in PE treatment. Animal and clinical studies in addition to its pharmacokinetic document dapoxetine’s clinical efficacy and safety for on-demand treatment of PE.

Conclusions

Dapoxetine demonstrates clinical efficacy and a favorable side effect profile. Dapoxetine is currently the oral drug of choice for on-demand treatment of PE.

Is thyroid hormones evaluation of clinical value in the work-up of males of infertile couples?

STUDY QUESTION

Is thyroid hormones (TH) evaluation of clinical value in the work-up of males of infertile couples?

STUDY ANSWER

Our results suggest that TH evaluation is not mandatory in the work-up of male infertility.

WHAT IS KNOWN ALREADY

A few previous studies performed on a limited series of subjects reported a negative impact of hyper- and hypo-thyroidism on semen volume, sperm concentration, progressive motility and normal morphology. No previous study has systematically evaluated associations between TH variation, semen parameters and ultrasound characteristics of the male genital tract.

STUDY DESIGN, SIZE AND DURATION

Cross-sectional analysis of a consecutive series of 172 subjects seeking medical care for couple infertility from September 2010 to November 2014.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Of the entire cohort, 163 men (age 38.9 ± 8.0 years) free of genetic abnormalities were studied. All subjects underwent a complete andrological and physical examination, biochemical and hormonal assessment, scrotal and transrectal colour-Doppler ultrasound (CDUS) and semen analysis (including seminal interleukin 8 levels, sIL-8) evaluation within the same day.

MAIN RESULTS AND THE ROLE OF CHANCE

Among the patients studied, 145 (88.9%) showed euthyroidism, 6 (3.7%) subclinical hyper- and 12 (7.4%) subclinical hypo-thyroidism. No subjects showed overt hyper- or hypo-thyroidism. At univariate analysis, no associations among thyroid-stimulating hormone (TSH) or TH levels and sperm parameters were observed. Conversely, we observed positive associations among free triiodothyronine (fT3) and free thyroxine (fT4) levels, ejaculate volume and seminal fructose levels. In a multivariate model, after adjusting for confounders such as age, body mass index, smoking habit, sexual abstinence, calculated free testosterone, prolactin and sIL-8 levels, only the associations found for fT3 levels were confirmed. When CDUS features were investigated, using the same multivariate model, we found positive associations between fT3 levels and seminal vesicles (SV) volume, both before and after ejaculation (adj. r = 0.354 and adj. r = 0.318, both P < 0.0001), as well as with SV emptying (ΔSV volume; adj. r = 0.346, P < 0.0001) and echo-texture inhomogeneity. In addition, after adjusting for confounders, negative associations between fT4 levels and epididymal body and tail diameters were found. No significant associations between TSH or TH levels and CDUS features of other organs of the male genital tract, including testis and prostate, were found. Finally, when the features of subjects with euthyroidism, subclinical hypo- and hyper-thyroidism were compared, no significant differences in seminal or hormonal parameters were found. Conversely, evaluating CDUS parameters, subjects with subclinical hyperthyroidism showed a higher difference between the SV longitudinal diameters measured before and after ejaculation when compared with that of subclinical hypothyroid men, even after adjusting for confounders (P < 0.007). All the other male genital tract CDUS characteristics did not differ among groups.

LIMITATIONS, REASONS FOR CAUTION

First, the number of patients investigated is relatively small and those with (subclinical) thyroid dysfunctions are an even smaller number; hence, it is therefore difficult to draw firm conclusions. Moreover, the present results are derived from patients consulting an Italian Andrology Clinic for couple infertility, and could have different characteristics from the male general population or from those males consulting general practitioners for reasons other than couple infertility. Finally, due to the cross-sectional nature of the study, neither a causality hypothesis nor mechanistic models can be inferred.

WIDER IMPLICATIONS OF THE FINDINGS

Although no associations between TH and sperm parameters were observed, present data support a positive effect of TH on SV size and a permissive role on the ejaculatory machinery, likely through an action on SV and epididymal contractility. This is the first study reporting such evidence. However, in contrast with the view that TH assessment is important for female fertility, our results do not support a systematic evaluation of thyroid function in males of infertile couples. How TH abnormalities impact male fertility needs to be addressed by further studies.

STUDY FUNDING/COMPETING INTERESTS

No funding was received for the study. None of the authors have any conflict of interest to declare.

Normal male sexual function: emphasis on orgasm and ejaculation

Orgasm and ejaculation are two separate physiological processes that are sometimes difficult to distinguish. Orgasm is an intense transient peak sensation of intense pleasure creating an altered state of consciousness associated with reported physical changes. Antegrade ejaculation is a complex physiological process that is composed of two phases (emission and expulsion), and is influenced by intricate neurological and hormonal pathways. Despite the many published research projects dealing with the physiology of orgasm and ejaculation, much about this topic is still unknown. Ejaculatory dysfunction is a common disorder, and currently has no definitive cure. Understanding the complex physiology of orgasm and ejaculation allows the development of therapeutic targets for ejaculatory dysfunction. In this article, we summarize the current literature on the physiology of orgasm and ejaculation, starting with a brief description of the anatomy of sex organs and the physiology of erection. Then, we describe the physiology of orgasm and ejaculation detailing the neuronal, neurochemical, and hormonal control of the ejaculation process.

Hormonal correlations of premature ejaculation

Premature ejaculation is the most frequent male sexual dysfunction, significantly impairing quality of life of both the patient and the partner and affecting up to one-third of men of every age. In the last years, our knowledge about this topic has greatly increased, and studies on the causes and treatments related to ejaculatory disorders have shed a light on previously uncharted territory. Public interest on sexual dysfunctions has likewise increased in the general population: the time lapse between the first symptoms of sexual dysfunction and the seeking of medical advice has been significantly reduced, whereas demand for a treatment has markedly increased. A role of endocrine regulation has been established in all the aspects of male reproduction; however, the endocrine control of ejaculation is not fully understood. Sex steroid, pituitary, and thyroid hormones have all been advocated as potential candidates in the regulation of the ejaculatory process, but exact mechanisms are not clear yet and further studies are required in order to identify potential targets for treatment.

An Update of the International Society of Sexual Medicine's Guidelines for the Diagnosis and Treatment of Premature Ejaculation (PE)

INTRODUCTION

In 2009, the International Society for Sexual Medicine (ISSM) convened a select panel of experts to develop an evidence-based set of guidelines for patients suffering from lifelong premature ejaculation (PE). That document reviewed definitions, etiology, impact on the patient and partner, assessment, and pharmacological, psychological, and combined treatments. It concluded by recognizing the continually evolving nature of clinical research and recommended a subsequent guideline review and revision every fourth year. Consistent with that recommendation, the ISSM organized a second multidisciplinary panel of experts in April 2013, which met for 2 days in Bangalore, India. This manuscript updates the previous guidelines and reports on the recommendations of the panel of experts.

AIM

The aim of this study was to develop clearly worded, practical, evidenced-based recommendations for the diagnosis and treatment of PE for family practice clinicians as well as sexual medicine experts.

METHOD

A comprehensive literature review was performed.

RESULTS

This article contains the report of the second ISSM PE Guidelines Committee. It offers a new unified definition of PE and updates the previous treatment recommendations. Brief assessment procedures are delineated, and validated diagnostic and treatment questionnaires are reviewed. Finally, the best practices treatment recommendations are presented to guide clinicians, both familiar and unfamiliar with PE, in facilitating treatment of their patients.

CONCLUSION

Development of guidelines is an evolutionary process that continually reviews data and incorporates the best new research. We expect that ongoing research will lead to a more complete understanding of the pathophysiology as well as new efficacious and safe treatments for this sexual dysfunction. We again recommend that these guidelines be reevaluated and updated by the ISSM in 4 years. Althof SE, McMahon CG, Waldinger MD, Serefoglu EC, Shindel AW, Adaikan PG, Becher E, Dean J, Giuliano F, Hellstrom WJG, Giraldi A, Glina S, Incrocci L, Jannini E, McCabe M, Parish S, Rowland D, Segraves RT, Sharlip I, and Torres LO. An update of the International Society of Sexual Medicine's guidelines for the diagnosis and treatment of premature ejaculation (PE). Sex Med 2014;2:60-90.

An update of the International Society of Sexual Medicine's guidelines for the diagnosis and treatment of premature ejaculation (PE)

INTRODUCTION

In 2009, the International Society for Sexual Medicine (ISSM) convened a select panel of experts to develop an evidence-based set of guidelines for patients suffering from lifelong premature ejaculation (PE). That document reviewed definitions, etiology, impact on the patient and partner, assessment, and pharmacological, psychological, and combined treatments. It concluded by recognizing the continually evolving nature of clinical research and recommended a subsequent guideline review and revision every fourth year. Consistent with that recommendation, the ISSM organized a second multidisciplinary panel of experts in April 2013, which met for 2 days in Bangalore, India. This manuscript updates the previous guidelines and reports on the recommendations of the panel of experts.

AIM

The aim of this study was to develop clearly worded, practical, evidenced-based recommendations for the diagnosis and treatment of PE for family practice clinicians as well as sexual medicine experts.

METHOD

A comprehensive literature review was performed.

RESULTS

This article contains the report of the second ISSM PE Guidelines Committee. It offers a new unified definition of PE and updates the previous treatment recommendations. Brief assessment procedures are delineated, and validated diagnostic and treatment questionnaires are reviewed. Finally, the best practices treatment recommendations are presented to guide clinicians, both familiar and unfamiliar with PE, in facilitating treatment of their patients.

CONCLUSION

Development of guidelines is an evolutionary process that continually reviews data and incorporates the best new research. We expect that ongoing research will lead to a more complete understanding of the pathophysiology as well as new efficacious and safe treatments for this sexual dysfunction. We again recommend that these guidelines be reevaluated and updated by the ISSM in 4 years.

The role of sympathetic and parasympathetic nerve systems on the smooth muscle of rat seminal vesicles - experimental results and speculation for physiological implication on ejaculation

Ejaculation is a process involving sympathetic and parasympathetic effects during different stages - emission and ejection. Some conditions of ejaculation dysfunction are associated with autonomic nerves. However, the exact effects of autonomic nerves on ejaculation are not well defined. Autonomic agonists induce different recorded trace patterns of seminal vesicular contraction. The different traces contain different components of phasic and tonic contraction, which may have physiological implications. In this study, we examined isolated rat seminal vesicle (SV) contraction by phenylephrine (PE), acetylcholine, and their respective antagonists and then speculated upon physiological roles of sympathetic and parasympathetic nerves on SV during ejaculation. We found that PE and Ach both achieved good contraction of rat SV. Compared to α1b for sympathetic and M1, M2 for parasympathetic receptors, α1a and M3 are the relatively dominant subtypes on rat SV. Adrenergic and cholinergic agonists cause different trace patterns of SV contraction. We speculated that the sympathetic effect is dominant during emission to squeeze seminal fluid out and that the parasympathetic effect is dominant during ejection to provide an anti-reflux effect on the ejaculatory duct.

The hormonal control of ejaculation

Hormones regulate all aspects of male reproduction, from sperm production to sexual drive. Although emerging evidence from animal models and small clinical studies in humans clearly point to a role for several hormones in controlling the ejaculatory process, the exact endocrine mechanisms are unclear. Evidence shows that oxytocin is actively involved in regulating orgasm and ejaculation via peripheral, central and spinal mechanisms. Associations between delayed and premature ejaculation with hypothyroidism and hyperthyroidism, respectively, have also been extensively documented. Some models suggest that glucocorticoids are involved in the regulation of the ejaculatory reflex, but corresponding data from human studies are scant. Oestrogens regulate epididymal motility, whereas testosterone can affect the central and peripheral aspects of the ejaculatory process. Overall, the data of the endocrine system in regulating the ejaculatory reflex suggest that widely available endocrine therapies might be effective in treating sexual disorders in these men. Indeed, substantial evidence has documented that treatments of thyroid diseases are able to improve some ejaculatory difficulties.

Medical therapy for premature ejaculation

Premature ejaculation (PE) is a common male sexual dysfunction. Advances in PE research have been hampered owing to a nonstandardized definition of PE, until the definition by the International Society of Sexual Medicine (ISSM) in 2009. Once the diagnosis of PE is established through a thorough history, a variety of medical therapies is available, including tricyclic antidepressants, selective serotonin reuptake inhibitors (SSRIs), centrally acting opiates, phosphodiesterase 5 inhibitors and topical desensitizing creams. Most of these treatments increase the intravaginal ejaculation latency time (IELT) and patient satisfaction scores, with the most convincing evidence for SSRIs and topical creams. Daily SSRIs such as paroxetine, although efficacious, do have a substantial and prolonged side effect profile. Dapoxetine, which is a on-demand SSRI, is the only licensed drug for the treatment of PE, increasing IELT by a factor of 2.5 to 3 with limited and tolerable side effects. In the near future, the topical aerosol PSD502 is due to be licensed for the treatment of PE, increasing IELT by up to a factor of 6 but having minimal local and negligible systemic side effects.