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Saúde reprodutiva – planeamento familiar conhecimentos e comportamentos sexuais dos adolescentes portugueses

Correia, Teresa
Fonte: Universidade do Porto-Faculdade de Medicina Publicador: Universidade do Porto-Faculdade de Medicina
Tipo: Tese de Doutorado
POR
Relevância na Pesquisa
36.24%
Sexual and Reproductive Health is one of the elements of the individuals general health, and has been a focus of interest in the developed countries. Lifestyle changes, namely in adolescents, will because a global problem. Sexual and Reproductive Health may produce two different feelings. On the one hard, it provides individual satisfaction and a feeling of well-being. On the other hand, misinformation or unreflected attitudes will provoke frustration and several unpleasant feelings. Usually, a person´s behaviour and/or ideas, thoughts and beliefs tend to be consolidated during the adolescence period and maintained throughout the adult life leading to high levels of morbidity and mortality, which represents high costs, both to the individual and also to the society in general. Therefore, it is extremely important to promote it throughout the education process. The first sexual experience is beginning to appear earlier than ever, which is considered a public health concern both in Portugal and in Europe. An early high-risk sexual behaviour, as well as the premature age of the first sexual experience is percetible throughout Europe. The prevalence of the contraceptive methods used is an important indicator in the evaluation of the level of exposure that adolescents experience...

Glyphosate impairs male offspring reproductive development by disrupting gonadotropin expression

Romano, Marco Aurelio; Romano, Renata Marino; Santos, Luciana Dalazen; Wisniewski, Patricia; Campos, Daniele Antonelo; Souza, Paula Bargi de; Viau, Priscila; Bernardi, Maria Martha; Nunes, Maria Tereza; Oliveira, Claudio Alvarenga de
Fonte: Springer Heidelberg; Heidelberg Publicador: Springer Heidelberg; Heidelberg
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.25%
Sexual differentiation in the brain takes place from late gestation to the early postnatal days. This is dependent on the conversion of circulating testosterone into estradiol by the enzyme aromatase. The glyphosate was shown to alter aromatase activity and decrease serum testosterone concentrations. Thus, the aim of this study was to investigate the effect of gestational maternal glyphosate exposure (50 mg/kg, NOAEL for reproductive toxicity) on the reproductive development of male offspring. Sixty-day-old male rat offspring were evaluated for sexual behavior and partner preference; serum testosterone concentrations, estradiol, FSH and LH; the mRNA and protein content of LH and FSH; sperm production and the morphology of the seminiferous epithelium; and the weight of the testes, epididymis and seminal vesicles. The growth, the weight and age at puberty of the animals were also recorded to evaluate the effect of the treatment. The most important findings were increases in sexual partner preference scores and the latency time to the first mount; testosterone and estradiol serum concentrations; the mRNA expression and protein content in the pituitary gland and the serum concentration of LH; sperm production and reserves; and the height of the germinal epithelium of seminiferous tubules. We also observed an early onset of puberty but no effect on the body growth in these animals. These results suggest that maternal exposure to glyphosate disturbed the masculinization process and promoted behavioral changes and histological and endocrine problems in reproductive parameters. These changes associated with the hypersecretion of androgens increased gonadal activity and sperm production.; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq); Conselho Nacional de Desenvolvimento Cientifico e Tecnologico-CNPq [151485/2010-0]

Estereótipos de gênero e cuidado em saúde sexual de mulheres lésbicas e bissexuais; Gender stereotypes and sexual healthcare concerning lesbians and bisexual women

Rodrigues, Julliana Luiz
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 26/08/2011 PT
Relevância na Pesquisa
36.32%
O aumento da visibilidade de mulheres que se relacionam com mulheres tem suscitado questões pertinentes à saúde desse grupo. A literatura aponta que estereótipos de gênero e valores acerca da masculinidade e feminilidade se fazem presentes nos discursos e interferem nas ações de cuidado com a saúde. A falta de orientação nos atendimentos ginecológicos pertinentes a sua prática sexual é apontada como uma dificuldade encontrada por mulheres que se relacionam com mulheres. A saúde sexual, localizada como direito do sujeito, deve ser pensada incluindo-se aspectos sociais como determinantes para a qualidade da atenção dispensada. Este trabalho tem por objetivo compreender como as construções de gênero se fazem presentes nas relações homo-afetivas entre mulheres e no cuidado dedicado à saúde sexual. Pautada em vertente qualitativa, utilizou-se de entrevistas semi-estruturadas e anotações em diário de campo para obtenção dos dados. Entrevistou-se nove mulheres lésbicas ou bissexuais entre 19 e 46 anos, todas residentes na cidade de São Paulo. As entrevistas foram gravadas, transcritas e analisadas a partir das categorias gênero, práticas preventivas e cuidado em saúde. Os resultados permitem vislumbrar a relação entre diferentes construções do ser mulher e o cuidado dispensado à saúde sexual. Maior dificuldade em perceber necessidade de cuidado e de buscar serviços de saúde esteve presente entre mulheres lésbicas que se reconheciam masculinizadas. Valores relativos à feminilidade hegemônica...

Adult partner preference and sexual behavior of male rats exposed prenatally to betamethasone

Piffer, Renata C.; Garcia, Patricia C.; Pereira, Oduvaldo C. M.
Fonte: Pergamon-Elsevier B.V. Ltd Publicador: Pergamon-Elsevier B.V. Ltd
Tipo: Artigo de Revista Científica Formato: 163-167
ENG
Relevância na Pesquisa
86.58%
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Processo FAPESP: 06/57038-6; The aim of this Study was to investigate long-term effects of prenatal betamethasone exposure oil sexual partner preference, testosterone level, and sexual behavior. Pregnant rats received 0.1 mg/kg of betamethasone or saline on the 12th, 13th, 18th, and 19th days of pregnancy. Parameters in male offspring were evaluated at 90 days of age. Male rats from the betamethasone group did not show any difference in sexual partner preference as expressed by the total number of visits to the female or male zone. However, these males spent significantly less total time and shorter duration per visit in the female zone than their controls. Therefore, prenatal exposure to betamethasone led to a significantly lower sexual female partner preference score compared to the control group. These animals also presented diminished testosterone levels in adulthood. Prenatal exposure to betamethasone induced a delay in the latency to first ejaculation. as well as a decrease in the numbers of postejaculatory intromissions, total intromissions and total ejaculations. Although 80% of the betamethasone-treated animals exhibited male Sexual behavior...

Prenatal testosterone supplementation alters puberty onset, aggressive behavior, and partner preference in adult male rats

Dela Cruz, Cynthia; Pereira, Oduvaldo C. M.
Fonte: Springer Tokyo Publicador: Springer Tokyo
Tipo: Artigo de Revista Científica Formato: 123-131
ENG
Relevância na Pesquisa
46.24%
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); The objective of this study was to investigate whether prenatal exposure to testosterone (T) could change the body weight (BW), anogenital distance (AGD), anogenital distance index (AGDI), puberty onset, social behavior, fertility, sexual behavior, sexual preference, and T level of male rats in adulthood. To test this hypothesis, pregnant rats received either 1 mg/animal of T propionate diluted in 0.1 ml peanut oil or 0.1 ml peanut oil, as control, on the 17th, 18th and 19th gestational days. No alterations in BW, AGD, AGDI, fertility, and sexual behavior were observed (p > 0.05). Delayed onset of puberty (p < 0.0001), increased aggressive behavior (p > 0.05), altered pattern of sexual preference (p < 0.05), and reduced T plasma level (p < 0.05) were observed for adult male rats exposed prenatally to T. In conclusion, the results showed that prenatal exposure to T was able to alter important aspects of sexual and social behavior although these animals were efficient at producing descendants. In this sense more studies should be carried to evaluated the real impact of this hormonal alteration on critical period of sexual differentiation on humans, because pregnant women exposed to hyperandrogenemia and then potentially exposing their unborn children to elevated androgen levels in the uterus can undergo alteration of normal levels of T during the sexual differentiation period...

PARTNER PREFERENCE IN MALE HAMSTERS: STEROIDS, SEXUAL EXPERIENCE AND CHEMOSENSORY CUES

Ballard, Cortney L.; Wood, Ruth I.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.65%
This study investigated the effects of gonadal steroids on sexual motivation in male Syrian hamsters, using partner preference as a model. Male hamsters were assigned to 5 groups: control (n=4), Intact→Orchx (n=8), Orchx→Orchx+T (n=7), olfactory bulbectomy (BulbX, n=5), and vomeronasal organ lesion (VnoX, n=8). Each male was tested for partner preference before and after sexual experience. Unlike rats, sexually-inexperienced gonad-intact male hamsters preferred the receptive female to a stimulus male. However, sexual experience did not enhance preference for the stimulus female. Castration (orchx) reduced sexual motivation: OrchX males showed no significant preference for the stimulus female. Subsequently, intact males were castrated (Intact→Orchx) and OrchX males received a testosterone implant (Orchx→Orchx+T) to determine the time course of gonadal hormones on partner preference and mating behavior. Partner preference changed significantly in both groups within 6 weeks. In Intact→Orchx males, preference for the stimulus female decreased while Orchx→Orchx+T males increased their preference for the stimulus female. However, significant changes in mating behavior preceded the alterations in partner preference. Chemosensory cues are also important for partner preference. After BulbX...

The Ram as a Model for Behavioral Neuroendocrinology

Perkins, Anne; Roselli, Charles E.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
36.17%
The sheep offers a unique model to study male sexual behavior and sexual partner preference. Rams are seasonal breeders and show the greatest libido during short days coincident with the resumption of ovarian cyclicity in the ewe. Threshold concentrations of testosterone are required for the acquisition and display of adult sexual behavior. In addition, estrogens produced from circulating testosterone by cytochrome P450 aromatase in the preoptic area are critical for the maintenance of sexual behaviors in rams. Sex differences in adult reproductive behaviors and hormone responsiveness are the result of permanent organizational effects exerted by testosterone and its metabolites on brain development. Early exposure to ewes enhances ram sexual performance, but cannot prevent some rams from exhibiting male-oriented sexual partner preferences. Neurochemical and neuroanatomical studies suggest that male-oriented ram behavior may be a consequence of individual variations in brain sexual differentiation.

FEMALE GONADAL HORMONES, MILD RESTRAINT, AND MALE PREFERENCE

Uphouse, L.; Hiegel, C.; Sarkar, J.; Hurlburt, J.; Templeton, C.; Guptarak, J.; Maswood, N.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/2008 EN
Relevância na Pesquisa
36.15%
The partner preference paradigm was used to test the hypothesis that mild restraint reduced sexual motivation of female rats. Ovariectomized rats were primed with 10 µg estradiol benzoate or estradiol benzoate and 500 µg progesterone. Additional rats were injected with sesame seed oil. These three groups of rats (oil-oil, estradiol benzoate-oil, or estradiol benzoate-progesterone; OO, EO, EP) were placed for 10 min in an arena, the ends of which enclosed either a sexually active male or an ovariectomized, unprimed female. Time spent near the sexually active male relative to time spent near either stimulus animal was used as the index of male preference. As expected, hormonal treatment significantly increased male preference. After this first 10 min interval, females were returned to the home cage or restrained for 5 min in a Decapicone®. Thereafter, male preference was recorded for another 10 min. Consistent with the first 10 min period, EP rats spent significantly more time near the male than did OO rats while EO rats were intermediate. There was no effect of restraint, but there was a significant increase in self-grooming. These findings contrast with previous studies and allow the suggestion that a brief, mild restraint fails to influence the female’s sexual motivation. The implications of these findings are discussed.

Prenatal Programming of Sexual Partner Preference: The Ram Model

Roselli, C.E.; Stormshak, F.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /03/2009 EN
Relevância na Pesquisa
66.46%
In our laboratory the domestic ram is used as an experimental model to study the early programming of neural mechanisms underlying same-sex partner preference. This interest developed from the observation that ∼8% of domestic rams are sexually attracted to other rams (male-oriented) in contrast to the majority of rams that are attracted to oestrous ewes (female-oriented). One prominent feature of sexual differentiation in many species is the presence of a sexually dimorphic nucleus (SDN) in the preoptic/anterior hypothalamus that is larger in males than in females. Lesion studies in rats and ferrets implicate the SDN in the expression of sexual preferences. We discovered an ovine SDN (oSDN) in the preoptic/anterior hypothalamus that is smaller in male- than in female-oriented rams and similar in size to the oSDN of ewes. Neurons of the oSDN show abundant aromatase expression that is also reduced in male-oriented compared to female-oriented rams. This observation suggests that sexual partner preferences are neurologically hard-wired and could be influenced by hormones. Aromatase-containing neurons constitute a nascent oSDN as early as d 60 of gestation, which becomes sexually dimorphic by d 135 of gestation when it is 2 times larger in males than in females. Exposure of fetal female lambs to exogenous testosterone from d 30 to 90 of gestation resulted in a masculinised oSDN. These data demonstrate that the oSDN develops prenatally and may influence adult sexual preferences. Surprisingly...

The Neurobiology of Sexual Partner Preferences in Rams

Roselli, Charles E.; Stormshak, Fred
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/2009 EN
Relevância na Pesquisa
46.43%
The question of what causes a male animal to seek out and choose a female as opposed to another male mating partner is unresolved and remains an issue of considerable debate. The most developed biologic theory is the perinatal organizational hypothesis, which states that perinatal hormone exposure mediates sexual differentiation of the brain. Numerous animal experiments have assessed the contribution of perinatal testosterone and/or estradiol exposure to the development of a male-typical mate preference, but almost all have used hormonally manipulated animals. In contrast, variations in sexual partner preferences occur spontaneously in domestic rams, with as many as 8% of the population exhibiting a preference for same-sex mating partners (male-oriented rams). Thus, the domestic ram is an excellent experimental model to study possible links between fetal neuroendocrine programming of neural mechanisms and adult sexual partner preferences. In this review, we present an overview of sexual differentiation in relation to sexual partner preferences. We then summarize results that test the relevance of the organizational hypothesis to expression of same-sex sexual partner preferences in rams. Finally, we demonstrate that the sexual differentiation of brain and behavior in sheep do not depend critically on aromatization of testosterone to estradiol.

Sexual differentiation of pheromone processing: Links to male-typical mating behavior and partner preference

Baum, Michael J.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/2009 EN
Relevância na Pesquisa
46.15%
Phoenix et al. (Phoenix et al., 1959) were the first to propose an essential role of fetal testosterone exposure in the sexual differentiation of the capacity of mammals to display male-typical mating behavior. In one experiment control male and female guinea pigs as well as females given fetal testosterone actually showed equivalent levels of mounting behavior when gonadectomized and given ovarian steroids prior to adult tests with a stimulus female. This finding is discussed in the context of a recent, high-profile paper by Kimchi and co-workers (Kimchi et al., 2007) arguing that female rodents possess the circuits that control the expression of male-typical mating behavior and that their function is normally suppressed in this sex by pheromonal inputs that are processed via the vomeronasal organ (VNO)—accessory olfactory nervous system. In another Phoenix et al. experiment, significantly more mounting behavior was observed in male guinea pigs and in females given fetal testosterone than in control females following adult gonadectomy and treatment with testosterone. Literature is reviewed that attempts to link sex differences in the anatomy and function of the accessory versus the main olfactory projections to the amygdala and hypothalamus to parallel sex differences in courtship behaviors...

Estrogen treatment during development alters adult partner preference and reproductive behavior in female laboratory rats

Henley, C.L.; Nunez, A.A.; Clemens, L.G.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.31%
There is broad acceptance for the idea that during development estradiol ‘organizes’ many aspects of reproductive behavior including partner preferences in the laboratory rat. With respect to partner preference, this idea is drawn from studies where estrogen action was in someway blocked, either through aromatase or estrogen receptor inhibition, during development in male rats. The lack of estrogens neonatally results in a decrease in the male rat’s preference for females. In this study, the effect of early postnatal estradiol treatment on the partner preferences of female rats was examined as a further test of the hypothesis that male-typical partner preference is dependent upon early exposure to estrogens. Our principal finding was that increased postnatal estradiol exposure during development affected partner preference in the expected direction, and this effect was seen under several adult hormonal and behavioral testing conditions. Female rats that received exogenous estradiol during development spent more time with an estrous female and less time with a sexually active male than did cholesterol treated females. The estradiol treatment also disrupted normal female sexual behavior, receptivity, and proceptivity.

Evaluation of two automated metrics for analyzing partner preference tests

Ahern, Todd H.; Modi, Meera E.; Burkett, James P.; Young, Larry J.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.31%
The partner preference test (PPT) is commonly used to examine sexual and social preferences in rodents. The test offers experimental subjects a choice between two stimulus animals, and time spent with each is used to calculate a preference score. In monogamous prairie voles (Microtus ochrogaster), the PPT has been paramount to the study of pair bonding. Although powerful, use of the PPT in voles has depended primarily on human manual scoring. Manual scoring is time-consuming and is susceptible to bias and fatigue, limiting the use of the PPT in high-throughput studies. Here we compared manual scoring (real-time and 16x) and two automated scoring metrics: “social proximity” and “immobile social proximity” We hypothesized that “immobile social contact” would provide data most comparable to manually scored “huddling”, and thus be the most sensitive measure of partner preference in prairie voles. Each automated metric produced data that highly correlated with manual scoring (R > 0.90); however, “immobile social contact” more closely reflected manually scored huddling (R = 0.99; P < 0.001). “Social proximity” and “immobile social contact” were then used to detect group partner preferences in four data sets that varied by cohabitation length and sex. “Immobile social contact” revealed a significant partner preference in each data set; “social proximity” detected partner preferences in only three of the four. Our results demonstrate the utility of automated systems in high-throughput PPTs...

Exogenous Androgen during Development Alters Adult Partner Preference and Mating Behavior in Gonadally Intact Male Rats

Henley, C.L.; Nunez, A.A.; Clemens, L.G.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.49%
In the rat, neonatal administration of testosterone propionate to a castrated male causes masculinization of behavior. However, if an intact male is treated neonatally with testosterone (hyper-androgen condition), male sexual behavior in adulthood is disrupted. There is a possibility that the hyper-androgen treatment is suppressing male sexual behavior by altering the male’s partner preference and thereby reducing his motivation to approach the female. If so, this would suggest that exposure to supra-physiological levels of androgen during development may result in the development of male-oriented partner preference in the male. To test this idea, male rats were treated either postnatally or prenatally with testosterone, and partner preference and sexual behavior were examined in adulthood. The principal finding of this study was that increased levels of testosterone during early postnatal life, but not prenatal, decreased male sexual behavior and increased the amount of time a male spent with a stimulus male, without affecting the amount of time spent with a stimulus female during partner preference tests. Thus, the reduction in male sexual behavior produced by early exposure to high levels of testosterone is not likely due to a reduction in the male’s motivation to approach a receptive female.

The Development of Male-Oriented Behavior in Rams

Roselli, Charles E.; Reddy, Radhika; Kaufman, Katherine
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
36.36%
The sheep offers a unique mammalian model in which to study paradoxical same-sex sexual partner preferences. Variations in sexual partner preferences occur spontaneously with as many as 8% of rams in a population exhibiting a sexual preference for other rams (male-oriented). The current review presents an overview and update of the male-oriented ram model and discusses several theories that have been invoked to explain same sex preferences in this species. Although our understanding of the biological determinants and underlying neural substrates of sexual attraction and mate selection are far from complete, compelling evidence is discussed that supports the idea that neural substrates regulating sexual partner preferences are organized during prenatal development. The challenge for future research will be to construct an integrated picture of how hormones, genes, and experience shape sexual partner preference.

Wired on Steroids: Sexual Differentiation of the Brain and Its Role in the Expression of Sexual Partner Preferences

Alexander, Brenda M.; Skinner, Donal C.; Roselli, Charles E.
Fonte: Frontiers Research Foundation Publicador: Frontiers Research Foundation
Tipo: Artigo de Revista Científica
Publicado em 03/10/2011 EN
Relevância na Pesquisa
56.56%
The preference to seek out a sexual partner of the opposite sex is robust and ensures reproduction and survival of the species. Development of female-directed partner preference in the male is dependent on exposure of the developing brain to gonadal steroids synthesized during critical periods of sexual differentiation of the central nervous system. In the absence of androgen exposure, a male-directed partner preference develops. The development and expression of sexual partner preference has been extensively studied in rat, ferret, and sheep model systems. From these models it is clear that gonadal testosterone, often through estrogenic metabolites, cause both masculinization and defeminization of behavior during critical periods of brain development. Changes in the steroid environment during these critical periods result in atypical sexual partner preference. In this manuscript, we review the major findings which support the hypothesis that the organizational actions of sex steroids are responsible for sexual differentiation of sexual partner preferences in select non-human species. We also explore how this information has helped to frame our understanding of the biological influences on human sexual orientation and gender identity.

The role of conditioning on heterosexual and homosexual partner preferences in rats

Coria-Avila, Genaro A.
Fonte: Co-Action Publishing Publicador: Co-Action Publishing
Tipo: Artigo de Revista Científica
Publicado em 15/03/2012 EN
Relevância na Pesquisa
36.21%
Partner preferences are expressed by many social species, including humans. They are commonly observed as selective contacts with an individual, more time spent together, and directed courtship behavior that leads to selective copulation. This review discusses the effect of conditioning on the development of heterosexual and homosexual partner preferences in rodents. Learned preferences may develop when a conditioned stimulus (CS) is associated in contingency with an unconditioned stimulus (UCS) that functions as a reinforcer. Consequently, an individual may display preference for a partner that bears a CS. Some UCS may be more or less reinforcing, depending on when they are experienced, and may be different for males and females. For example, it could be that, only during periods of early development, that stimuli associated with nurture and juvenile play become conditioned. In adulthood, other stimuli such as sexual reward, cohabitation, mild stress, or even pharmacological manipulations may function as reinforcers to condition partner preferences. Evolutionary biologists and psychologists must take into consideration the idea that an individual’s experience with reward (i.e. sexual and pharmacological) can override presumably ‘innate’ mate choices (e.g. assortativeness and orientation) or mate strategies (e.g. monogamy or polygamy) by means of Pavlovian and operant contingencies. In fact...

Brain Serotonin Signaling Does Not Determine Sexual Preference in Male Mice

Angoa-Pérez, Mariana; Herrera-Mundo, Nieves; Kane, Michael J.; Sykes, Catherine E.; Anneken, John H.; Francescutti, Dina M.; Kuhn, Donald M.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 23/02/2015 EN
Relevância na Pesquisa
36.35%
It was reported recently that male mice lacking brain serotonin (5-HT) lose their preference for females (Liu et al., 2011, Nature, 472, 95–100), suggesting a role for 5-HT signaling in sexual preference. Regulation of sex preference by 5-HT lies outside of the well established roles in this behavior established for the vomeronasal organ (VNO) and the main olfactory epithelium (MOE). Presently, mice with a null mutation in the gene for tryptophan hydroxylase 2 (TPH2), which are depleted of brain 5-HT, were tested for sexual preference. When presented with inanimate (urine scents from male or estrous female) or animate (male or female mouse in estrus) sexual stimuli, TPH2-/- males show a clear preference for female over male stimuli. When a TPH2-/- male is offered the simultaneous choice between an estrous female and a male mouse, no sexual preference is expressed. However, when confounding behaviors that are seen among 3 mice in the same cage are controlled, TPH2-/- mice, like their TPH2+/+ counterparts, express a clear preference for female mice. Female TPH2-/- mice are preferred by males over TPH2+/+ females but this does not lead to increased pregnancy success. In fact, if one or both partners in a mating pair are TPH2-/- in genotype...

The Ovine Sexually Dimorphic Nucleus, Aromatase, and Sexual Partner Preferences in Sheep

Roselli, C.E.; Stormshak, F.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
56.18%
We are using the domestic ram as an experimental model to examine the role of aromatase in the development of sexual partner preferences. This interest has arisen because of the observation that as many as 8% of domestic rams are sexually attracted to other rams (male-oriented) in contrast to the majority of rams that are attracted to estrous ewes (female-oriented). Our findings demonstrate that aromatase expression is enriched in a cluster of neurons in the medial preoptic nucleus called the ovine sexually dimorphic nucleus (oSDN). The size of the oSDN is associated with a ram's sexual partner preference, such that the nucleus is 2 -3 times larger in rams that are attracted to females (female-oriented) than in rams that are attracted to other rams (male-oriented). Moreover, the volume of the oSDN in male-oriented rams is similar to the volume in ewes. These volume differences are not influenced by adult concentrations of serum testosterone. Instead, we found that the oSDN is already present in late gestation lamb fetuses (∼ day 135 of gestation) when it is ∼2-fold greater in males than in females. Exposure of genetic female fetuses to exogenous testosterone during the critical period for sexual differentiation masculinizes oSDN volume and aromatase expression when examined subsequently on day 135. The demonstration that the oSDN is organized prenatally by testosterone exposure suggests that the brain of the male-oriented ram may be under-androgenized during development.

Preference for dry sex, condom use and risk of STI among HIV-negative black women in the Western Cape province, South Africa

Reddy,Priscilla; Saleh-Onoya,Dorina; Sifunda,Sibusiso; Lang,Delia; Wingood,Gina; Borne,Bart van den; Ruiter,Robert A.C.
Fonte: South African Journal of Science Publicador: South African Journal of Science
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2009 EN
Relevância na Pesquisa
36.2%
The practice of dry sex is reportedly common among young black women in South Africa. The aim of this study was to explore the relationship of women's preference for dry sex with condom use and the prevalence of Chlamydia trachomatis (CT), Neisseria gonorrhoea (NG) and Trichomonas vaginalis (TV) infections. Between January 2006 and December 2007, 446 women completed a behavioural survey in isiXhosa which assessed demographic information, sexual behaviours, condom use behaviour and other potential correlates. In total, 159 (36.72%) women indicated preferring dry sex. A multivariate logistic regression model indicated that participants who preferred dry sex were more likely to report past STI episodes and to have a partner who also preferred dry sex. The findings indicate that dry sex behaviour was not directly associated with condom use and STI (CT, NG, and TV) prevalence but may have been associated with relationships in which sexual preferences of the male partner were dominant.