Androgens and male behavior

Hormonal contraception and cognition: Considering the influence of endogenous ovarian hormones and genes for clinical translation

Despite the well-known influence of ovarian hormones on the brain and widespread use of hormonal contraception (HC) since the 1960s, our knowledge of HC's cognitive effects remains limited. To date, the cognitive findings have been inconsistent. In order to establish what might make HC studies more consistent, we surveyed the literature on HCs and cognition to determine whether studies considered HC formulation, phase, pharmacokinetics, duration, and gene interactions, and assessed whether oversight of these factors might contribute to variable findings. We found that synthetic HC hormones exert dose-dependent effects, the day of oral contraceptive (Pill) ingestion is critical for understanding cognitive changes, and gene-cognition relationships differ in women taking the Pill likely due to suppressed endogenous hormones. When these factors were overlooked, results were not consistent. We close with recommendations for research more likely to yield consistent findings and be therefore, translatable.

Inactivation of Cops5 in Smooth Muscle Cells Causes Abnormal Reproductive Hormone Homeostasis and Development in Mice

COP9 constitutive photomorphogenic homolog subunit 5 (COPS5), also known as Jab1 or CSN5, has been implicated in a wide variety of cellular and developmental processes. By analyzing male germ cell-specific COPS5-deficient mice, we have demonstrated previously that COPS5 is essential to maintain male germ survival and acrosome biogenesis. To further determine the role of Cops5 in peritubular myoid cells, a smooth muscle lineage surrounding seminiferous tubules, we herein derived mice conditionally deficient for the Cops5 gene in smooth muscle cells using transgenic Myh11-Cre mice. Although these conditional Cops5-deficient mice were born at the expected Mendelian ratio and appeared to be normal within the first week after birth, the homozygous mice started to show growth retardation after 1 week. These mice also exhibited a variety of developmental and reproductive disorders, including failure of development of reproductive organs in both males and females, spermatogenesis defects, and impaired skeletal development and immune functions. Furthermore, conditional Cops5-deficient mice revealed dramatic impairment of the endocrine system associated with testicular functions, including a marked reduction in serum levels of gonadotropins (follicle-stimulating hormone, luteinizing hormone), testosterone, insulin-like growth factor 1, and glucose, but not vasopressin. All homozygous mice died before age 67 days in the study. Collectively, our results provide novel evidence that Cops5 in smooth muscle lineage plays an essential role in postnatal development and reproductive functions.

Sex differences in opioid receptor mediated effects: Role of androgens

An abundance of data indicates there are sex differences in endogenous opioid peptides and opioid receptors, leading to functional differences in sensitivity to opioid receptor mediated behaviors between males and females. Many of these sex differences are mediated by the effects of gonadal hormones on the endogenous opioid system. Whereas much research has examined the role of ovarian hormones on opioid receptor mediated endpoints, comparatively less research has examined the role of androgens. This review describes what is currently known regarding the influence of androgens on opioid receptor mediated endpoints and how androgens may contribute to sex differences in these effects. The review also addresses the clinical implications of androgenic modulation of opioid receptor mediated behaviors and suggests future lines of research for preclinical and clinical investigators. We conclude that further investigation into androgenic modulation of opioid receptor mediated effects may lead to new options for addressing conditions such as chronic pain and substance use disorders.

Sexual motivation: problem solved and new problems introduced

Background During the past 50 years, motivational studies have evolved from the logical inference of logically required "intervening variables" to explain behavioral change, to electrophysiological and molecular analyses of the mechanisms causing such changes. Aim The purpose of this review article is two-fold: first to describe the logic of sexual motivation in a way that applies to laboratory animals as well as humans, and the second is to address some of the problems of sexual motivation experienced by men. Results When problems of motivational mechanisms are stripped down to their essentials, as performed in the laboratory animal models and are available for reductionistic studies, then the problems can be solved with certainty, as illustrated in the first part of this review. However, with respect to human sexual motivation, the various determinants which include so many behavioral routes and so many brain states come into play, that definite conclusions are harder to come by, as illustrated in the second part of this review. Conclusions This review highlights a number of key questions that merit further investigation. These include (a) What mechanisms do cultural and experiential influences interact with androgenic hormone influences on human sexual motivation? (b) How would epigenetic effects in the human brain related to changes in motivation be investigated? (c) What are the effects of unpredictable traumatic and stressful human experiences on sexual motivation; (d) How such mechanisms are activated upon unpredictable traumatic and stressful insults? (e) What are the outstanding differences between sexual motivational drive and motivations driven by homeostatic systems such as hunger and thirst?

Sexual orientation related differences in cortical thickness in male individuals

Previous neuroimaging studies demonstrated sex and also sexual orientation related structural and functional differences in the human brain. Genetic information and effects of sex hormones are assumed to contribute to the male/female differentiation of the brain, and similar effects could play a role in processes influencing human's sexual orientation. However, questions about the origin and development of a person's sexual orientation remain unanswered, and research on sexual orientation related neurobiological characteristics is still very limited. To contribute to a better understanding of the neurobiology of sexual orientation, we used magnetic resonance imaging (MRI) in order to compare regional cortical thickness (Cth) and subcortical volumes of homosexual men (hoM), heterosexual men (heM) and heterosexual women (heW). hoM (and heW) had thinner cortices primarily in visual areas and smaller thalamus volumes than heM, in which hoM and heW did not differ. Our results support previous studies, which suggest cerebral differences between hoM and heM in regions, where sex differences have been reported, which are frequently proposed to underlie biological mechanisms. Thus, our results contribute to a better understanding of the neurobiology of sexual orientation.

Estrogen, schizophrenia and neurodevelopment

Women are relatively protected against schizophrenia. The illness has a similar rate in women and men, but it starts later in women and is less severe. It is tempting to attribute this to the neuroprotective effect of estrogen, but the story is not straightforward and contains many unknowns. Women begin their schizophrenia trajectory later in development compared with men and this probably accounts for their relatively superior prognosis. Estrogen agonists are potential therapeutic agents but need to be proven safe, and the timing of administration may be crucial. This article examines what is known about estrogen and the development of schizophrenia.

Introduction to the interaction between gonadal steroids and the central nervous system

The sex steroids are frequently referred to as the gonadal steroids and are erroneously assumed to be exclusively linked to the ovaries in women or the testes in men and the functions of the reproductive tract. This chapter will provide an overview of some of the extragonadal effects of these hormones, focusing on the central nervous system, and the mechanisms of hormone action. Hormone synthesis and metabolism within the CNS will be discussed with particular focus on the role of aromatase. Sex steroids exert many of their effects via intracellular receptors and these genomic responses tend to be slow in onset, however, some responses to steroids occur more quickly and are mediated via membrane receptors and involve interactions with many different transduction pathways to produce a diverse array of responses. These complexities do pose challenges but also offer opportunity for novel approaches for therapeutic exploitation as the pharmacological tools with which to modulate systems become increasingly available.

Effect of Mucuna pruriens (Linn.) on sexual behavior and sperm parameters in streptozotocin-induced diabetic male rat

INTRODUCTION

Sexual dysfunction is one of the major secondary complications in the diabetic. Mucuna pruriens, a leguminous plant identified for its antidiabetic, aphrodisiac, and improving fertility properties, has been the choice of Indian traditional medicine.

AIM

Objective of the present study was to analyze the efficacy of M. pruriens on male sexual behavior and sperm parameters in long-term hyperglycemic male rats.

METHODS

Male albino rats were divided as group I control, group II diabetes induced (streptozotocin [STZ] 60 mg/kg of body weight (b.w.) in 0.1 M citrate buffer), group III diabetic rats administered with 200 mg/kg b.w. of ethanolic extract of M. pruriens seed, group IV diabetic rats administered with 5 mg/kg b.w. of sildenafil citrate (SC), group V administered with 200 mg/kg b.w. of extract, and group VI administered with 5 mg/kg b.w. of SC. M. pruriens and SC were administered in single oral dosage per day for a period of 60 days. The animals were subjected to mating behavior analyses, libido, test of potency, and epididymal sperms were analyzed.

MAIN OUTCOME MEASURE

The mating behavior, libido, test of potency, along with epididymal sperms were studied.

RESULTS

The study showed significant reduction in sexual behavior and sperm parameters in group II. Daily sperm production (DSP) and levels of follicular stimulating hormone, luteinizing hormone, and testosterone were significantly reduced in group II, whereas the animals with diabetes administered with seed extract of M. pruriens (group III) showed significant improvement in sexual behavior, libido and potency, sperm parameters, DSP, and hormonal levels when compared to group II.

CONCLUSION

The present work reveals the potential efficacy of ethanolic seed extract of M. pruriens to improve male sexual behavior with androgenic and antidiabetic effects in the STZ-induced diabetic male rats. This study supports the usage of M. pruriens in the Indian system of medicine as sexual invigorator in diabetic condition and encourages performing similar study in men.

Timetable of effects of testosterone administration to hypogonadal men on variables of sex and mood

INTRODUCTION

The effects of testosterone have been extensively characterized, but little attention has been given to the timetable of occurrence of the various effects of testosterone.

METHODS

The timetables of effects on sexual and psychological variables in 40 hypogonadal men receiving treatment with either parenteral testosterone enanthate (TE) or undecanoate (TU).

RESULTS

Sexual thoughts/fantasies and sexual interest/desire/spontaneous morning erections emerged quickly and plateaued after 3 weeks. Total erections rose to a maximum over 9 weeks and then plateaued. Ejaculations per week/satisfaction with sex life rose over the first 3 weeks, increasing steadily to a plateau at 12 weeks. Depression scores decreased to reach a plateau after 6 weeks. Aggressiveness did not change. Scores of concentration improved and reached a plateau after 3 weeks in the group treated with TE and after 9 weeks in the group treated with TU. Good mood improved after 6-9 weeks. Positive effects on self-confidence appeared between 3-6 weeks and on fatigue after 9-12 weeks.

CONCLUSION

Insight into the emergence of effects may be useful information for the patient and for the attending physician in monitoring clinical effects of testosterone treatment of hypogonadal men.

Sex Hormones and Cognitive Functioning of Women

U radu se raspravlja o organizirajućim i aktivirajućim učincima spolnih hormona te o njihovu utjecaju na kognitivno funkcioniranje. Dosadašnja su istraživanja pokazala spolne razlike u nekim specifičnim kognitivnim sposobnostima. Žene su u prosjeku bolje u verbalnoj fluentnosti, perceptivnoj brzini i točnosti, kao i finijoj motorici, dok su muškarci u prosjeku bolji u prostornim i matematičkim sposobnostima. Ove razlike u kognitivnom funkcioniranju dovode se u vezu s izlaganjem mozga fetusa različitim razinama spolnih hormona tijekom prenatalnog života. Studije na skupinama rođenim s genskim poremećajima, kao što su sindrom neosjetljivosti na androgene, kongenitalna adrenalna hiperplazija i Turnerov sindrom također upućuju na organizirajuće učinke spolnih hormona na kognitivno funkcioniranje.

Nadalje, dosadašnja istraživanja pokazuju da povišene razine ženskih spolnih hormona u kasnoj folikularnoj i/ili lutealnoj fazi menstrualnog ciklusa potenciraju tipičan ženski kognitivni obrazac funkcioniranja, koji karakterizira veća učinkovitost u zadacima koje u prosjeku bolje rješavaju žene. Niske pak razine ovih hormona, koje karakteriziraju menstrualnu fazu ciklusa, potenciraju tipičan muški obrazac funkcioniranja, koji uključuje bolju učinkovitost u zadacima koje u prosjeku bolje rješavaju muškarci.

U radu se također raspravlja o metodološkim razlikama u dosadašnjim istraživanjima organizirajućih i aktivirajućih učinaka spolnih hormona na kognitivno funkcioniranje, kao i o smjernicama za buduća istraživanja.

Finger length ratio (2D:4D) in adults with gender identity disorder

From early childhood, gender identity and the 2nd to 4th finger length ratio (2D:4D) are discriminative characteristics between sexes. Both the human brain and 2D:4D may be influenced by prenatal testosterone levels. This calls for an examination of 2D:4D in patients with gender identity disorder (GID) to study the possible influence of prenatal testosterone on gender identity. Until now, the only study carried out on this issue suggests lower prenatal testosterone levels in right-handed male-to-female GID patients (MtF). We compared 2D:4D of 56 GID patients (39 MtF; 17 female-to-male GID patients, FtM) with data from a control sample of 176 men and 190 women. Bivariate group comparisons showed that right hand 2D:4D in MtF was significantly higher (feminized) than in male controls, but similar to female controls. The comparison of 2D:4D ratios of biological women revealed significantly higher (feminized) values for right hands of right handed FtM. Analysis of variance confirmed significant effects for sex and for gender identity on 2D:4D ratios but not for sexual orientation or for the interaction among variables. Our results indirectly point to the possibility of a weak influence of reduced prenatal testosterone as an etiological factor in the multifactorially influenced development of MtF GID. The development of FtM GID seems even more unlikely to be notably influenced by prenatal testosterone.

Prenatal sex hormones (maternal and amniotic fluid) and gender-related play behavior in 13-month-old Infants

Testosterone, estradiol, and progesterone levels were measured in the second trimester of pregnancy in maternal serum and amniotic fluid, and related to direct observations of gender-related play behavior in 63 male and 63 female offspring at age 13 months. During a structured play session, sex differences in toy preference were found: boys played more with masculine toys than girls (d = .53) and girls played more with feminine toys than boys (d = .35). Normal within-sex variation in prenatal testosterone and estradiol levels was not significantly related to preference for masculine or feminine toys. For progesterone, an unexpected significant positive relationship was found in boys between the level in amniotic fluid and masculine toy preference. The mechanism explaining this relationship is presently not clear, and the finding may be a spurious one. The results of this study may indicate that a hormonal basis for the development of sex-typed toy preferences may manifest itself only after toddlerhood. It may also be that the effect size of this relationship is so small that it should be investigated with more sensitive measures or in larger populations.

Androgen cell signaling pathways involved in neuroprotective actions

As a normal consequence of aging in men, testosterone levels significantly decline in both serum and brain. Age-related testosterone depletion results in increased risk of dysfunction and disease in androgen-responsive tissues, including brain. Recent evidence indicates that one deleterious effect of age-related testosterone loss in men is increased risk for Alzheimer's disease (AD). We discuss recent findings from our laboratory and others that identify androgen actions implicated in protecting the brain against neurodegenerative diseases and begin to define androgen cell signaling pathways that underlie these protective effects. Specifically, we focus on the roles of androgens as (1) endogenous negative regulators of beta-amyloid accumulation, a key event in AD pathogenesis, and (2) neuroprotective factors that utilize rapid non-genomic signaling to inhibit neuronal apoptosis. Continued elucidation of cell signaling pathways that contribute to protective actions of androgens should facilitate the development of targeted therapeutic strategies to combat AD and other age-related neurodegenerative diseases.

The biology of human psychosexual differentiation

Most attempts to identify biological underpinnings of gender identity and sexual orientation in humans have investigated effects of sex steroids, so pivotal in the differentiation of the genitalia, showing strong parallels between animals and the human. The information on humans is derived from the so-called 'experiments of nature', clinical entities with a lesser-than-normal androgen exposure in XY subjects and a higher than normal androgen exposure in XX subjects. Prenatal androgenization appears to predispose to a male gender identity development, but apparently not decisively since 40-50% of 46,XY intersexed children with a history of prenatal androgen exposure do not develop a male gender identity. Obviously, male-to-female transsexuals, with a normal androgen exposure prenatally (there is no serious evidence to the contrary) develop a female gender identity, through unknown biological mechanisms apparently overriding the effects of prenatal androgens. The latest studies in 46, XX subjects exposed to prenatal androgens show that prenatal androgenization of 46,XX fetuses leads to marked masculinization of later gender-related behavior but does not lead to gender confusion/dysphoria. The example of female-to-male transsexuals, without evidence of prenatal androgen exposure, indicates that a male gender identity can develop without a significant androgen stimulus. So we are far away from any comprehensive understanding of hormonal imprinting on gender identity formation. Brain studies in homosexuals have not held up in replication studies or are in need of replication in transsexuals. Genetic studies and the fraternal birth order hypothesis provide indications of familial clustering of homosexuality but in many homosexuals these genetic patterns cannot be identified. The biological explanations advanced for the birth order hypothesis lack any experimental support.

Efecto del retardo de crecimiento intrauterino sobre el dimorfismo sexual en recien nacidos de termino: una adaptación prenatal en perspectiva evolutiva

OBJETIVOS: identificar si se modifica el dismorfismo sexual del crecimiento frente a retardo de crecimiento intrauterino. MÉTODOS: se compararon 4931 recién nacidos con (n=497) y sin (n=4434) retardo de crecimiento intrauterino. Todos fueron de término (para Argentina >37 semanas). La población se dividió en dos grupos de acuerdo a la condición de crecimiento fetal y el sexo. Los indicadores antropométricos del crecimiento prenatal incluyeron el peso corporal, la longitud y el perímetro cefálico. RESULTADOS: no hubo diferencias estadísticas significativas entre sexos en el peso al nacer y la longitud corporal en neonatos con retardo de crecimiento intrauterino. De forma contraria, los neonatos con crecimiento fetal normal evidenciaron diferencias significativas en ambos indicadores entre sexos siendo más grandes los varones. CONCLUSIONES: la inhibición del dismorfismo sexual está ya presente en etapas prenatales cuando ocurre una situación que afecte el crecimiento como es el caso del retardo de crecimiento intrauterino. Se considera la perspectiva evolutiva de dicho fenómeno inhibitorio.

Androgen excess in women--a health hazard?

A significant body of evidence suggests that androgens in women may play a role in the genesis of central adiposity and type 2 diabetes. There are two principal sources of circulating androgens in females: the ovary and the adrenal gland. In hyperandrogenic women, there are elevated serum concentrations of androstenedione and testosterone and, in up to 50% of the women, dehydroepiandrosterone sulfate (DHEAS). The androgen precursor DHEAS is of exclusive adrenal origin, suggesting that hyperandrogenic women have an elevated proportion of adrenal androgen production and secretion. Another cause of androgen excess in reproductive-age women is a decreased conversion of testosterone to estradiol by the aromatase enzyme complex. In this review, we will discuss the hypothesized clinical sequel of elevated androgens in women - an aspect of women's health highly neglected. Furthermore, an attempt is made to appreciate what causes the androgens to initially rise from normal levels, allowing the onset of pathophysiological processes towards diseases.

Pathways of endocrine disruption during male sexual differentiation and masculinization

After testis formation, further development of a male phenotype (masculinization) is driven by three hormones from the foetal testis: anti-Müllerian hormone, insulin-like factor 3, and testosterone. These hormones divert the development of reproductive and other organs from female to male and also play a role in testis development. The hormone dependence of masculinization renders this process inherently susceptible to disruption by factors that interfere with hormone production, bioavailability, metabolism, or action. This susceptibility is illustrated by the high prevalence of congenital masculinization disorders (cryptorchidism, hypospadias) and disorders in young adult men (low sperm counts, testis cancer), which may also stem from maldevelopment (dysgenesis) of the foetal testis. Testicular dysgenesis occurring in humans, or which is induced in animal models by foetal exposure to certain phthalates, is associated with impaired hormone production by the foetal testis. There is currently no definitive evidence that exposure of humans to environmental chemicals can induce testicular dysgenesis and/or impair masculinization, though pathways via which this could potentially occur are established.

Intersexed states: diagnosis and management

Traditional guidelines for the care of intersexed patients have been questioned by dissatisfied adult intersexed patients. The controversy surrounding this issue comes from a handful of highly publicized intersexed cases with poor outcomes, representing a minority of the intersexed population, which serve as an appropriate call to reassess this difficult issue. Re-evaluation of management strategies must acknowledge the complaints of those who oppose the traditional management paradigm and address scientific and surgical advancements and the roles they should play. This article reviews these issues, attempts to formulate a contemporary approach, and acknowledges the gaps that remain in our knowledge.

Estrogen-receptor-? distribution in the human hypothalamus: Similarities and differences with ER? distribution

This study reports the first systematic rostrocaudal distribution of estrogen receptor beta immunoreactivity (ER beta-ir) in the human hypothalamus and adjacent areas in five males and five females between 20-39 years of age and compares its distribution to previously reported ER alpha in the same patients. ER beta-ir was generally observed more frequently in the cytoplasm than in the nucleus and appeared to be stronger in women. Basket-like fiber stainings, suggestive for ER beta-ir in synaptic terminals, were additionally observed in various areas. Men showed more robust nuclear ER beta-ir than women in the medial part of the bed nucleus of the stria terminalis, paraventricular and paratenial nucleus of the thalamus, while less intense, but more nuclear, ER beta-ir appeared to be present in, e.g., the BSTc, sexually dimorphic nucleus of the medial preoptic area, diagonal band of Broca and ventromedial nucleus. Women revealed more nuclear ER beta-ir than men of a low to intermediate level, e.g., in the suprachiasmatic, supraoptic, paraventricular, infundibular, and medial mamillary nucleus. These data indicate potential sex differences in ER beta expression. ER beta-ir expression patterns in subjects with abnormal hormone levels suggests that there may be sex differences in ER beta-ir that are "activational" rather than "organizational" in nature. Similarities, differences, potential functional, and clinical implications of the observed ER alpha and ER beta distributions are discussed in relation to reproduction, autonomic-function, mood, cognition, and neuroprotection in health and disease.

Early social stress in male Guinea-pigs changes social behaviour, and autonomic and neuroendocrine functions

The present study was undertaken to investigate the effects of pre- and early postnatal social stress on the functioning of hormonal, autonomic and behavioural systems, by studying the distribution of sex hormone receptors in limbic brain systems. Dams had either lived in groups with a constant composition (= stable social environment) or in groups with changing compositions, i.e. every third day, two females from different groups were exchanged (= unstable social environment). The subjects were male offspring of dams who had either lived in a stable social environment during pregnancy and lactation (= control males) or in an unstable social environment during this period of life (= early stressed males). From days 20-80, the spontaneous behaviour of control males and early stressed males was recorded in their home cages. Five control males and five early stressed males were killed at 75 days, and five control males and five early stressed males at 120 days. Blood samples were taken to determine serum concentrations of cortisol, testosterone, dehydroepiandrosterone, dehydroepiandrosterone sulphate and oestrogen. The adrenals were prepared to determine tyrosine hydroxylase activities and the brains were used to investigate the distribution of sex-hormone receptors in specific hypothalamic and hippocampal brain areas. Early stressed males showed a behavioural infantilization that was accompanied by significantly decreased adrenal tyrosine hydroxylase activities and dehydroepiandrosterone levels. Furthermore, early stressed males showed a down-regulation of androgen receptors in the medial preoptic area and the nucleus arcuatus of the hypothalamus, as well as of oestrogen receptor alpha in the hippocampus compared to control males. Thus, the present study provides clear evidence that early social stress induces changes in endocrine, autonomic and limbic brain function, which is mirrored by changes in male social behaviour.